Foundational SEO Knowledge
1. What is SEO?
SEO (Search Engine Optimization) is the practice of increasing the quantity and quality of traffic to a website through organic search engine results.
2. What are the main categories of SEO?
On-Page SEO, Off-Page SEO, and Technical SEO. Some also include Local SEO and Content SEO as distinct pillars.
3. What is a search engine crawler?
A bot (like Googlebot) that systematically browses the web to discover new and updated pages to be added to the search index.
4. What is the difference between indexing and crawling?
Crawling is the process of discovering pages. Indexing is the process of analyzing a page’s content and meaning, then storing it in a massive database from which it can be retrieved for search results.
5. What is a SERP?
Search Engine Results Page — the page displayed by a search engine in response to a user’s query.
6. What is organic traffic?
Visitors who land on your website from unpaid, natural search engine results, as opposed to paid ads.
7. What is a search engine algorithm?
A complex system of rules and calculations used to retrieve data from the search index and instantly deliver the best possible results for a query.
8. Name the major search engines.
Google, Bing, Yahoo, Yandex (Russia), Baidu (China), DuckDuckGo.
9. What is the difference between White Hat and Black Hat SEO?
White Hat uses search-engine-approved techniques focused on a human audience. Black Hat exploits weaknesses in algorithms for quick gains, risking penalties.
10. What is a long-tail keyword?
A specific, usually longer search phrase (3+ words) with lower search volume but higher purchase intent and lower competition (e.g., “best running shoes for flat feet women”).
On-Page SEO
11. What is a title tag and why is it important?
An HTML element specifying a webpage’s title. It appears as the clickable headline in SERPs and is a strong relevance signal for search engines. Best practice: under 60 characters, include primary keyword, brand name.
12. What is a meta description?
An HTML attribute providing a brief page summary. Though not a direct ranking factor, it heavily influences click-through rate (CTR). Best practice: under 160 characters, compelling copy with keyword inclusion.
13. What is the difference between an H1 and an H2 tag?
H1 is the main heading (usually one per page, reflecting the primary topic). H2s are subheadings that break content into logical sections. H3s nest under H2s, etc.
14. What is keyword cannibalization?
When multiple pages on your site target the same keyword intent, causing them to compete against each other and dilute authority. Fix by merging or differentiating content.
15. Why is image alt text important?
It describes an image to search engines (for ranking in Image Search) and screen readers (accessibility). It also serves as anchor text if an image is a link.
16. What is internal linking?
Hyperlinks that point from one page on a domain to another page on the same domain. They help distribute page authority and establish site architecture.
17. What is anchor text?
The clickable text in a hyperlink. Descriptive, relevant anchor text helps search engines understand the context of the linked page.
18. What is SEO-friendly URL structure?
Short, readable URLs that include the target keyword, use hyphens to separate words, and avoid unnecessary parameters or session IDs.
19. What is keyword density, and does it still matter?
The percentage of times a keyword appears relative to total word count. No fixed ideal density exists anymore; copy should read naturally while covering topics comprehensively (TF-IDF/natural language processing focus).
20. How do you optimize a page for featured snippets?
Identify snippet opportunities (paragraph, list, table), structure content to directly and concisely answer the query (40-60 words for paragraphs), and use proper HTML markup (lists, tables).
Off-Page SEO & Link Building
21. What is a backlink?
An incoming hyperlink from one website to another. They are considered “votes of confidence” and are a top ranking factor.
22. What is Domain Authority (DA)?
A proprietary metric developed by Moz predicting how likely a domain is to rank. It’s not a Google metric but a comparative tool.
23. What makes a high-quality backlink?
From a relevant, authoritative domain; placed within main content (not footer/sidebar); uses natural anchor text; drives referral traffic; usually “dofollow.”
24. What is the difference between a dofollow and nofollow link?
Dofollow passes link equity (PageRank) and ranking signals. Nofollow (rel="nofollow") instructs search engines not to crawl or pass credit. Newer attributes include sponsored and ugc.
25. What is link building outreach?
The process of contacting other relevant websites to secure a backlink, often via guest posting, broken link building, or promoting a resource.
26. What is a toxic backlink?
Links from spammy, irrelevant, or link-farm sites that can trigger a manual penalty or algorithmic devaluation. Disavowal may be necessary.
27. What is the Google Disavow tool?
A tool in Search Console allowing you to upload a file telling Google to ignore certain links pointing to your site. Use with extreme caution.
28. What is Digital PR in the context of SEO?
Using PR strategies (press releases, journalist outreach, data campaigns) to earn high-authority, editorial backlinks from news and publication sites.
29. What is broken link building?
Finding dead external links on relevant sites, creating a similar resource on your site, then notifying the site owner to replace the broken link with yours.
30. What is a link farm?
A group of websites that all hyperlink to every other site in the group, created solely to manipulate search engine ranking. Penalizable.
Technical SEO
31. What is a robots.txt file?
A text file in a website’s root directory that instructs search engine crawlers which pages or sections of a site should not be crawled. Note: it does not prevent indexing if linked to externally.
32. What is an XML sitemap?
A file listing a website’s important pages, ensuring search engines can find and crawl all essential content, especially pages not well-linked internally.
33. What is canonicalization?
Using the rel="canonical" tag to tell search engines the “preferred” version of a page, preventing duplicate content issues when multiple URLs serve similar content.
34. What is a 301 redirect vs. a 302 redirect?
301 is a permanent redirect (passes most link equity). 302 is a temporary redirect (does not necessarily pass full equity, as the original URL will be indexed again).
35. What is HTTPS and is it a ranking factor?
Hypertext Transfer Protocol Secure. It encrypts data between browser and server. Yes, Google uses it as a lightweight ranking signal.
36. How does page speed affect SEO?
Page experience signals (Core Web Vitals) are official ranking factors. Slow sites hurt crawl budgets and user experience, leading to lower conversions and rankings.
37. What are Core Web Vitals?
Google’s metrics for UX: Largest Contentful Paint (LCP – loading), First Input Delay (FID – interactivity, replaced by Interaction to Next Paint – INP), and Cumulative Layout Shift (CLS – visual stability).
38. What is schema markup (structured data)?
Code added to a page to help search engines understand the content’s context, enabling rich results like review stars, recipe cards, and event details.
39. How do you fix duplicate content?
Use 301 redirects, rel="canonical" tags, cohesive internal linking to the canonical version, or manage URL parameters in Search Console.
40. What is a crawl budget?
The number of URLs a search engine bot will crawl on your site during a given session. Important for large websites; optimize by eliminating low-value URLs, fixing redirect chains, and improving speed.
41. What are orphan pages?
Pages that exist on a domain but have zero internal links pointing to them, making them difficult (or impossible) for crawlers and users to find.
42. What is hreflang?
An HTML attribute used to specify the language and geographical targeting of a webpage, crucial for international SEO and avoiding duplicate content across regional variants.
43. What is the difference between a client-side and server-side rendered page?
Client-side: JavaScript builds the page in the browser (tougher for crawlers). Server-side: The server sends fully rendered HTML, which is much easier for search engines to index reliably.
44. What is pagination and how do you handle it for SEO?
Splitting content across multiple pages (e.g., category pages, long articles). Best practice is a “view-all” page or using proper rel="prev"/"next" links along with self-referencing canonicals (though Google has deprecated the prev/next signal, clean internal linking remains key).
45. How do you migrate a site without losing SEO traffic?
Plan meticulously: complete URL mapping, implement 301 redirects for all changed URLs, maintain content, move XML sitemaps, update internal links, monitor via Search Console.
Content & Strategy
46. What is the difference between a topic and a keyword?
A keyword is a specific search phrase; a topic is a broader subject area covering multiple related queries and user intents.
47. What is search intent?
The “why” behind a search query. Four main types: Informational (know), Navigational (go), Commercial Investigation (choose), Transactional (buy).
48. How do you perform keyword research?
Start with a seed topic, use tools (Ahrefs, Semrush, Google Keyword Planner) to generate ideas, analyze search volume, keyword difficulty, and SERP features, then cluster keywords by parent topic and intent.
49. What is a content gap analysis?
Comparing the keyword profiles of your site with competitors to find topics they rank for that you don’t, revealing high-opportunity content ideas.
50. What is cornerstone content?
Comprehensive, authoritative articles on your site covering broad core topics. They are heavily internally linked from related supporting pages.
51. What is E-E-A-T and why does it matter?
Experience, Expertise, Authoritativeness, Trustworthiness. These are guidelines from Google’s Quality Rater Guidelines, especially critical for YMYL (Your Money or Your Life) niches.
52. How do you optimize existing content?
Update with current data, improve readability, expand shallow sections, optimize for new keyword variants, refresh images, reinvigorate internal links, and update the “last modified” date where relevant.
53. What is topical authority?
Building broad and deep expertise on a subject by creating interconnected, high-quality content that covers an entire topic cluster, making your site a go-to resource.
54. How do you create a content brief for writers?
Provide target primary and secondary keywords, suggested H2/H3 structure, recommended word count, competitor examples, internal linking opportunities, target audience, and tone of voice.
55. What is a pillar page and topic cluster model?
A broad pillar page covering a core topic, linked to multiple cluster pages covering specific, related subtopics. This structure signals topical authority.
56. What is CTR in SEO and how do you improve it?
Click-Through Rate (clicks/impressions). Improve by writing compelling, keyword-rich title tags and meta descriptions, using structured data for rich snippets, and ensuring URLs are clean.
57. How do you reduce bounce rate?
Improve page speed, match content exactly to user intent, enhance readability (short paragraphs, images, fonts), add clear internal navigation and relevant CTAs.
58. What does “content is king” mean in modern SEO?
While technical SEO allows discovery, content satisfies user intent. Without high-quality, valuable content, backlinks and rankings won’t sustain.
Analytics, Tools & KPIs
59. What key metrics do you track in SEO?
Organic traffic, keyword rankings, CTR, impressions, conversion rate, pages per session, bounce rate, backlinks gained/lost, Core Web Vitals.
60. What is Google Search Console (GSC)?
A free Google service that monitors, maintains, and troubleshoots a site’s presence in Google Search results. It shows clicks, impressions, average position, index coverage, and manual actions.
61. What is the difference between Google Analytics sessions and users?
A user is a unique visitor. A session is a group of user interactions within a given timeframe (default 30 minutes). One user can have multiple sessions.
62. What is a “not provided” keyword in Google Analytics?
Organic keywords that are hidden due to Google’s secure search (encrypted queries). You can see them in GSC’s Performance report.
63. What are some common SEO tools you use?
Ahrefs (backlinks, keyword research), Semrush (competitive analysis), Screaming Frog (technical crawls), Google Search Console, Google Analytics, PageSpeed Insights, Looker Studio (reporting).
64. How do you measure the ROI of SEO?
Set up goal tracking in analytics (e-commerce revenue, lead form submissions). Compare assisted conversions and organic revenue against the cost of SEO investment (tools, content, labor).
65. What is a log file analysis?
Examining raw server logs to see exactly how search engine bots crawl your site. It reveals crawl frequency, heavy-crawled irrelevant pages, and wasted crawl budget.
66. How do you report SEO progress to a stakeholder who doesn’t understand SEO?
Focus on business metrics: organic revenue, leads generated, cost per acquisition vs. paid channels. Visualize keyword movement buckets (top 10, top 3) rather than average position.
67. What is Google Looker Studio (formerly Data Studio)?
A free visualization tool to create interactive dashboards by pulling data from sources like GSC, Google Analytics, and Ahrefs, useful for live KPI monitoring.
68. What is the difference between impressions and clicks in GSC?
An impression is a link to your site appearing in a search result a user viewed (doesn’t require scroll). A click is the user actually visiting the page from the SERP.
Algorithm Updates & Penalties
69. What was the Google Panda update?
Targeted thin, low-quality, and duplicate content. It rewarded high-quality, original content.
70. What was the Google Penguin update?
Targeted manipulative link schemes (buying links, over-optimized anchor text). Operates in real-time within the core algorithm now.
71. What is the Google Helpful Content Update (HCU)?
A sitewide signal assessing whether content is created primarily for humans and demonstrates first-hand experience, as opposed to being written solely for search engines.
72. What is a manual action penalty?
A human reviewer at Google determines pages/sites violate guidelines (spam, unnatural links). It results in a notification in GSC and often a drastic ranking drop.
73. How do you recover from an algorithmic update hit?
Audit the specific update’s targets (e.g., content quality, UX). Review top competitor sites that gained. Fix issues (remove unhelpful content, prune low-quality links) and be patient; improvement may wait for the next update refresh.
74. What is the “Sandbox” effect?
An observed phenomenon where new websites experience a period of suppressed rankings despite good optimization, often attributed to a lack of established trust signals. Google denies the existence of a specific sandbox filter.
75. What is a core update?
A broad, significant change to Google’s main ranking algorithms designed to improve search results overall. They can cause major ranking shifts and require holistic quality analysis.
Local SEO
76. What is a Google Business Profile (GBP)?
A free business listing from Google, appearing in Local Pack and Maps. It includes Name, Address, Phone number (NAP), reviews, hours, and photos.
77. What is NAP consistency?
Having your business Name, Address, and Phone number listed identically across all online platforms (directory citations, website, social media), which is a crucial local ranking factor.
78. What are local citations?
Online mentions of a local business’s NAP. They can occur on directories, apps, or social platforms. Quality and consistency matter heavily.
79. How do you optimize for “near me” searches?
Claim and fully optimize your GBP, ensure mobile-friendly design, embed a Google Map on the contact page, acquire positive reviews, and use local business schema.
80. What is the difference between Local Pack and organic results?
Local Pack is the map and top 3 business listings for a local query. Organic results are the standard 10 blue links below (or to the side of) the map.
Mobile & International SEO
81. What is mobile-first indexing?
Google uses the mobile version of a site’s content for indexing and ranking, instead of the desktop version.
82. How do you optimize for mobile SEO?
Ensure responsive design, compress images, utilize caching, avoid intrusive pop-ups, design for touch, and maintain parity between mobile and desktop content.
83. What is an AMP page?
Accelerated Mobile Pages, a deprecated lightweight HTML framework to load pages instantly. No longer a requirement for ranking or Top Stories carousel, as speed is now measured broadly.
84. What is the difference between a multilingual and a multi-regional site?
Multilingual targets different languages (e.g., English, Spanish). Multi-regional targets different geographic locations (e.g., USA, UK, Australia), potentially in the same language.
85. When would you use a subdomain vs. subdirectory for international SEO?
Subdirectory (example.com/fr/) is usually preferred as it consolidates domain authority. Subdomains (fr.example.com) can be used when regions operate fully independently, but they dilute authority.
Advanced & Problem-Solving Questions
86. What is the first thing you do when you see a sudden drop in organic traffic?
Check for manual actions in GSC, verify tracking code is working, check if the site is down/no-indexed, analyze which pages/topics dropped and if it correlates with a known algorithm update.
87. How do you perform a competitive SEO analysis?
Identify true SERP competitors (not just business competitors). Compare domain authority, backlink profiles, keyword overlap/gaps, content quality, site structure, and Core Web Vitals.
88. How do you work with a Product/Development team that refuses to prioritize SEO tasks?
Translate the request into business impact/revenue potential using case studies or data. Propose MVP (Minimum Viable Product) solutions, and schedule tickets well ahead of sprints to align with their timelines.
89. A page is crawled but not indexed. Why might this happen?
Poor content quality (thin/duplicate), noindex tag present, canonical pointing to a different page, or the page is not valuable enough to be included in Google’s index (crawled but not indexed report).
90. How do you handle parameterized URLs (e.g., ?session_id=123)?
Use the URL Parameters tool in GSC to define parameter behavior, and set a canonical tag to the clean version of the URL to consolidate signals.
91. What is a reverse proxy in an SEO context?
A server that sits in front of web servers and forwards client requests. It can be used to serve pre-rendered static HTML snapshots to search engine bots for JavaScript-heavy sites.
92. How does JavaScript SEO differ from traditional HTML SEO?
It requires ensuring client-side rendered content is accessible to Googlebot via proper rendering, server-side rendering, or dynamic rendering, and careful testing using tools like GSC’s URL Inspection Tool (which can show rendered screenshots).
93. What is link reclamation?
The process of finding unlinked brand mentions or instances where backlinks broke (linking to a deleted page) and contacting the site to correct the link, turning a mention/broken link into a valuable backlink.
94. What is the “Moving Man Method”?
Outreach tactic: find outdated links pointing to a competitor’s defunct resource (or a rebranded site), then pitch your superior, modern replacement.
95. How do you optimize a site that uses infinite scroll?
Replace infinite scroll with a “Load More” button with a distinct linkable URL, or support the pushState API to update the URL as the user scrolls, and ensure an HTML sitemap exists.
Situational & Behavioral Questions
96. Describe a time your SEO recommendation failed. What happened?
Select a real scenario: moving content without redirects, expecting immediate link gains, misinterpreting keyword intent. Focus on diagnostics, the lesson learned, and the subsequent process improvement.
97. How do you stay up-to-date with the SEO industry?
Follow Google Search Central blog, Search Engine Roundtable, Search Engine Journal, Ahrefs blog, Twitter/LinkedIn experts, and enterprise-level experimentation. Mention testing things yourself on a sandbox site.
98. You’ve been assigned a brand new website. Walk me through your first 30 days.
Day 1-7: Technical audit (indexing, crawling setup), keyword research, competitor gap analysis. Day 7-14: Build topic clusters, optimize site architecture, establish KPIs/base tracking. Day 14-30: Create prioritized content roadmap, initiate foundational link building (citations, partnerships).
99. How do you explain the impact of SEO to a small business owner who wants results “next week”?
“SEO is like building a reputation in a new city. You can pay for a billboard (PPC) for immediate visibility today. SEO is building your business’s deep roots, word-of-mouth, and trust so that eventually, people come to you naturally long after you stop paying for ads. It’s the most sustainable long-term client acquisition channel.”
100. What do you think is the future of SEO?
The shift from “search engine” to “answer engine” (SGE/AI Overviews), optimizing for zero-click searches, emphasizing experiential content (E-E-A-T), voice/multimodal search, and leveraging AI for efficiency (automated audits) but focusing human effort on strategy, unique data, and storytelling that AI can’t replicate.