Hmmm. Just took a look at the new Danny Sullivan newsletter and I quote:
"[Abbot Chambers, Excite's Senior Director of Search and Directory Products] said Excite is also making mroe use of link text, something that's been a key component of how Google works. The idea in that regard is that you examine words in or near the hyperlink to determine the relevance of the page being linked to. For instance, if a link says "Great Place For Books" and points to Amazon, then the usage of link text would understand that Amazon is relevant for the word "book."
I think that it's a part of the same idea referenced in the authority hubs [webmasterworld.com] thread. When trying to guage the likely quality of a site, polling third-party links TO it seems to be a good way to make a guess.