lucy24 - 10:27 pm on Mar 8, 2013 (gmt 0)
if i had to guess they include the "Jump to" link based on a preponderance of usage in inbound links.
Can't be the only variable, though. Admittedly it's hard to tell unless the request is from a search engine or similar, where you see the whole thing including fragment # in the Referer box. (Or in analytics. Piwik tracks fragments, so I assume GA does too.)
But I've got search-engine fragment visits that I'm tolerably sure haven't been linked in that form from anywhere on the outside. My own best guess is that they look for headers or do I mean headings? in the vicinity of the search term. If your target is clustered around an h3 near the bottom of the page, and that h3 has a name and/or id of its own, that's where the search engine sends you.
What I'm describing happens to the first fragment search that I ever noticed, a year or two back. But the one I currently see most often is also associated with an h3-- and the name of the anchor is one of the search terms.
:: pause for belated "D'oh!" moment ::
I just realized I've got one bit of local-anchor text that's common enough that it would show up in gwt if they listed it: The ubiquitous "back to top" that occurs several times on most pages.
:: quick detour to check ::
Nope, not there. That suggests they list cross-page anchor text but not same-page text. But there's no difference-- color coding or similar-- between your own linking text, whether full-page or fragment, and outside linking text.
Google? You listening? That would be useful.