Marcia - 4:26 am on Sep 29, 2008 (gmt 0)

There's a section in this document on Link Analysis (PDF) [nlp.stanford.edu] that gives a good explanation of hubs and authorities.

And here's Jon Kleinberg's classic publication, also PDF:

Authoritative Sources in a Hyperlinked Environment [cs.cornell.edu]

Hub: Links out to a lot of authoritative documents
Authority site: Linked to by a lot of authoritative documents

An "authority site" is what's often used to describe a site with "authoritative information" but that's not the same sense as how it's used in search.

Now, if you see Sitelinks for a generic keyword query, rather than a full domain "navigational query", then that might show something about authority - but it still isn't about trust.

I believe site links can be based on either hub or authority score for a site, given that the site content and navigation support the topic of the search term.

[edited by: Marcia at 4:30 am (utc) on Sep. 29, 2008]