Signal to BuildSIGNAL TO BUILD中文Owner sign in ↗Explore curated knowledge, course notes and methods, with their existing content and sources preserved.
This index lists complete English editions. Additional Chinese notes and bilingual updates remain available in the Chinese index.
A complete historical guide to startup judgment, product-market fit, early growth, go-to-market and scaling, with the published additions on consistent delivery, audience feedback and historical-score shortlisting through October 23, 2026.
A compilation of official original sources for the 5 major milestones in Google Search evolution: RankBrain (2015, first deep learning ranking system / apex predator example) + BERT (2019, Transformer understanding word-to-word relationships / 10% of US English queries affected / "for someone" example) + MUM (2021, T5 / 1000x BERT / 75 languages / multimodal / Mt. Fuji example / average 8 queries for complex tasks) + HCU (August 2022, site-level ML classifier / "written for ranking" detection) + AI Overviews (May 2024, custom Gemini / multi-step + planning + AI-organized + video search). **Pandu Nayak's February 2022 overview = the only official article that covers all 4 major milestones together**. These 5 are the "constitution" of Google ranking; E-E-A-T and Google's stance on AI content are all derived from them.
Canonicalization concepts + Google's automatic canonical selection signals (HTTPS/redirect/sitemap/rel=canonical/hreflang cluster); priority table for 4 specification methods (redirect strong → rel=canonical strong → sitemap weak); complete HTTP status code table (2xx/3xx/4xx/5xx/special 429) + impact on indexing and crawling; 5 redirect types + Apache/NGINX/PHP configurations; Permanent vs Temporary semantic differences; 2 site move playbooks (host change without URL change / domain change with URL change); for temporary outages, prefer limiting functionality over full shutdown; dual paths to ask Google to recrawl; troubleshooting for 6 major canonical issues + 14 anti-patterns.
Google's 3-layer mental model for crawling/indexing/rendering control. robots.txt (only controls crawling, not indexing) + 3 major limitations. noindex (meta tag + HTTP header) implementation and debugging. Full table of 11 valid rules + 3 historical rules for the robots meta tag. Element-level fine-grained control with data-nosnippet. X-Robots-Tag (Apache/NGINX configuration + regex adaptation for non-HTML files). The strictest rule wins in conflicts. The classic pitfall where robots.txt + noindex cancel each other out. Decision table for 4 methods of controlling content. Image removal special case (Googlebot-Image UA). Full list of 9 user-triggered fetchers (which ignore robots.txt). rel=sponsored/ugc/nofollow outbound link qualifiers.
The 6 surfaces where Ecommerce content appears on Google (Search/Images/Lens/Shopping tab/Business Profile/Maps). Pros and cons of 4 launch strategies for new sites (Grand reveal / Home page launch / Launch with stock unavailable / Soft launch). 2 paths for Product data: on-page structured data + Google Merchant Center feed (automated/manual/Content API); **Merchant Center is mandatory for the Shopping tab**. 6 major relevant SD types (BreadcrumbList / LocalBusiness / Organization / Product+ProductGroup / Review / VideoObject). Ecommerce-specific rules for URL structure (use `?key=value`, do not use `?value`, do not use fragment variants; variants can use path segments or query parameters; use the query-free version for canonical); 3 common mistakes (treating fragments as variants / multiple content pieces on the same URL / infinite URL space from timestamped URLs). Comparison of 3 pagination modes (Pagination / Load more / Infinite scroll) + requirements for unique URLs + sequential links + do not set the homepage as canonical + **next/prev is deprecated**. 13 review guidelines (expert perspective / quantification / competitor comparison / evolution / affiliate disclosure).
2 types of Googlebot (Smartphone primary / Desktop minority) + crawl limits (2MB for HTML / 64MB for PDF / resources counted independently / calculated before decompression) + verification (reverse DNS). All file types Google can index (flat / encoded / media). 6 URL structure best practices + 4 common problems (faceted navigation / parameter abuse / infinite calendar space / relative links). Links must use `<a href>` to be reliably crawled; 5 anchor text guidelines. 3 mobile-first indexing configurations (responsive preferred / dynamic serving / separate URLs) + 13 troubleshooting errors. 9 supported meta tags + 4 unsupported ones (meta-keyword/lang/next-prev/nositelinkssearchbox). 8-element whitelist for valid HTML <head>; iframes/img tags cut off subsequent reading. 5-step crawl troubleshooting + soft 404 fixes + If-Modified-Since 304 optimization + emergency 503/429 crawl reduction. For website testing, do not cloak / use 302 + rel=canonical. AMP overview + Viewer vs Signed Exchange + 3 complete removal paths.
When you need a sitemap (>500 pages / new site / rich media) and when you don’t; how to choose among the 3 formats XML/RSS-mRSS-Atom/text; hard limits of 50MB / 50,000 URLs; sitemap index solution for large sites (500 per site); 4 extension namespaces and combined usage; full table of required and optional fields for image/video/news sitemaps; 4 submission methods; two approaches for cross-site submission; 13 anti-patterns.
A synthesis of three perspectives on SEO × LLM positions. Covers Google Search Central (official: how-not-who framework + boundaries of scaled content abuse + the Who/How/Why three questions + AI Overviews / Succeeding in AI Search) / newtype comprehensive guide to llms.txt (two competing format proposals: the robots.txt-like Access Control Model + the Markdown-based Inference Guidance Model / Karpathy's "rewrite software infrastructure for Agents") / newtype knowledge system (wiki.newtype.pro third layer = publishing layer = proprietary "LLM-friendly corpus"). Covers Google's stance on AI content, the current state of the llms.txt proposal, compatibility between E-E-A-T and AI content, and infrastructure for the Agent era.
Overseas promotion practice accumulated from 226 posts: platform-specific SOPs for Reddit / Twitter / YouTube / TikTok / HackerNews / ProductHunt / Dev.to, overseas phone number/bank card/payment configuration, multi-Agent multi-browser multi-account matrix
A complete consolidated operations SOP for 6 platforms. Reddit 8-week cold start / Twitter 90-day real-person account + matrix / YouTube 50-channel matrix operation / HN 8-week account warming / Product Hunt anti-chart-rush roadmap / Dev.to cross-post matrix. Includes universal iron rules for AI writing, account warming discipline, and risk control.