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Reference pages, written to be read rather than skimmed for keywords.
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Answer extractability: can an AI quote your page?
The check reads your question-form headings and nothing under them. What that measures, what nobody can measure, and why one is a proxy for the other.
Trust and authorship signals a crawler can see
About, Contact and a privacy page are the reliable half. The authorship half is looser, and this is the page that says which is which.
The email-capture check that never looks at your form
It reads body text, and body text is defined as the page minus nav, header, footer, aside and form. What that means for a footer signup.
Does your copy read as AI-written?
Check Engine matches a register, not authorship. It cannot tell you who or what wrote a page. What it looks for, why it needs more than one tell, and what that finding is worth.
Who blocks Googlebot, and who blocks GoogleOther
We read robots.txt across a large public sample. A small share deny Googlebot and rather more deny GoogleOther: what that can, and cannot, tell you about a site.
Does Cloudflare block GPTBot?
Cloudflare changed what a new domain does by default, and the answer differs by which OpenAI crawler is asking. How to check your own.
What is ClaudeBot?
Anthropic's training crawler, and the two other Anthropic crawlers that decide whether Claude can find and quote you. What blocking each one does.
What is llms.txt?
A Markdown reading list for language models. What goes in it, how many large sites have one, and why Google says you do not need it.
What is a sitemap?
A list of the URLs you want search engines to find. What goes in one, which tags Google and Bing ignore, and what four real sitemaps showed.
What is alt text?
The words that stand in for an image. How to write them, when an empty alt is correct, and the length rule nobody official set.
What is structured data?
Markup that tells search engines what a page is about. The formats, what it cannot promise, and which features Google has retired.
What is robots.txt?
A request to crawlers about which URLs not to fetch. How the rules match, and why it can't keep a page out of search.
What is a 404 error?
The server found nothing at that address. When a 404 is harmless, when it isn't, and the soft 404 that looks fine and isn't.
What is a favicon?
The small icon for your site in tabs, bookmarks and search results. Google's current size and format rules.
What is HTTPS?
HTTP over an encrypted connection. What it proves and what it doesn't, and what browsers now do with sites that lack it.
What is a URL?
The address of a page, in five parts. Which parts are case-sensitive, and why search engines see some variants as different pages.
Does noindex stop AI crawlers?
noindex tells an indexer not to list a page; it cannot stop a crawler fetching it. What robots.txt and your server control instead, and which layer is refusing yours.
Click depth and orphan pages
How many clicks from the homepage a page sits, and which pages nothing links to. Plus the crawl conditions under which neither number means anything.
URL structure: checked vs folklore
What Check Engine actually enforces about URLs, and which popular rules have no published source behind them.
Page weight and how heavy is too heavy
Check Engine grades the HTML document, not the whole page, and says 'at least' when the read was capped.
How Check Engine decides what to fix first
Severity, impact, reach and effort: the formula an audit ranks your site with, written out.
AI crawler directives: which to block
Training crawlers and search crawlers are different decisions with different costs.
Is your page actually indexed?
Whether a page is in Google, Bing or Brave is a fact about their index, not your HTML. What Check Engine asks each engine, and the places it refuses to guess.
AI crawlers and your sitemap
A Sitemap: line is a non-group record, so every crawler is offered the same one, including the crawlers a site is trying to keep out.
www or no www, and whether it still matters
Every page-one result agrees you should pick one. None of them counted. We probed a random sample to see how many hosts still serve both.
Internal links that carry UTM parameters
A site tagging its own internal links splits its analytics and can split its canonical signals. We crawled a sample and counted, and the affected hosts split into two different problems.
Googlebot's 2MB cutoff
It reads the first 2MB and indexes that as the whole page. We measured well-known homepages and found five already past it.
How to tell whether an audit tool is lying to you
Four questions to ask of any SEO finding, each of them learned here by getting it wrong first.
What Check Engine got wrong, and the release that fixed it
A dated list of the findings Check Engine got wrong, how each was found, which release fixed it and the tests that hold it, then 15 worked cases of findings that looked wrong.
Log file analysis: what Googlebot actually fetched
A user-agent proves nothing, which is why Google publishes 2,181 crawler IP prefixes. Reading a log honestly, and where the dedicated tool wins.
Brand consistency: the question no crawler asks
Of 11 company sites linking social profiles, 9 declared none of them in schema. What the brand area checks, and where design tools beat it.
Domain authority without a subscription
Ranked from the public Common Crawl link graph. The useful part is what it says when it cannot see you, which is what it said about this site.
SEO monitoring: what changed, not what is wrong
Re-audits while the app is open, regressions first, and the two comparisons Check Engine refuses to make because the number would look useful and be wrong.
Conversion audit: 9 checks on your landing pages
Ranking and then failing to say what to do next costs the same as not ranking. The 9 mechanical checks, and the judgement calls Check Engine refuses to make for you.
Marketing tag audit: is your tracking on every page?
Tags are installed on templates; sites grow pages built from other templates. The 6 tracking checks, and the four-minute version you can do by hand.
The contact address that cannot receive mail
An address on a domain with no MX record bounces to the sender and never reaches you, and no tool asks whether yours works.
Which pages an AI answer replaces
Ranking and not being visited. Measured on two live sites (this one at 5% fully substitutable, a delicatessen at 0%), and three ways we measured it wrong first.
AI search visibility
The three gates a model has to clear before it can cite you (access, rendering and entity clarity) with measured data on who is blocking what.
What an SEO audit covers
Every area, in the order they should be worked, and the three tests a report has to pass to be worth acting on.
JavaScript rendering
What a crawler that does not run JavaScript misses. Measured on a page that serves 0 characters of text and renders 2,068.
sameAs and entity signals
The cheapest entity signal there is, and the share of major sites that skip it: measured, with the dataset attached.
Canonical tags
Google calls rel=canonical a hint and overrules it routinely. The seven ways it gets set wrong, and what each Search Console status is actually telling you.
Internal link equity
The ranking signal your pages pass to each other, measured on our own site. Where the download page held a fifth of what an average page did.
What Check Engine checks
All the checks, by area, with what each one actually looks at.