'Coherent' Links: Do Relevant Links Count More?

Coherent and 'relevant' links do not exist at all.

[bundy_app]

All SEOs say that a link is 'havier' if it comes from a page which has the same contents of the linked page; but I'd like to know how google - which is a lexical se and not a semantic one - can know the 'subject' of a site? Google can only know if a page contain a keyword but noothing about its subject.

[MHes]

Hi
If google does a normal set of results for a search term and then looks at the linking structure between those pages it has found it can find 'on theme' links.