Relative canonical
OpportunityLow priority
Pages whose canonical is written as a relative address rather than a full one.
Why it matters
It works until something changes what it resolves against - a base tag, a moved template, a page served at two paths - and then it quietly names the wrong address.
How to fix it
Write canonicals in full, beginning with the scheme and host.
Skitter runs this check on every crawl, and lists each page it finds with the evidence: the header, the tag or the link that gave it away.