The Internal Link Checker reads the links on one page and splits them into internal and external. It checks for at least 5 internal links, generic anchor text like "read more", links with no text, nofollowed internal links and at least 2 external links. It also lists the internal pages that page links to most often, with a count for each.
Updated
The headline gives the number of internal and external links on the page. The stats add the number of unique internal targets, and each of the 5 checks comes back as a pass or a warning.
Only the links on the page you enter are counted. Links from other pages to this one are not part of the result.
Enough internal links warns when the page has fewer than 5. Descriptive anchor text warns on links whose text is just click here, here, read more, learn more, this, link or more. No empty anchors counts links that have no text, which is common with image-only links.
No nofollowed internal links warns when a link to your own site carries rel=nofollow. Links out to sources warns when the page has fewer than 2 external links.
The table lists up to 12 internal URLs with the number of times the page links to each. Anchors that point to the same page with a different #fragment count as one target. Navigation and footer links are included, so they often sit at the top.
Peak Answer runs checks like these every week, then writes the content and gets the placements.