Google’s problem, at this point, is that a lot of the “others” being “passively” indexed are spammers trying to game its algorithms. Google would be foolish not to leverage its money and its brand recognition to find ways to work around this problem with curated data. A link from a page with a trusted author is worth a hundred or more links from pages that are just randomly found by a crawler.

(Disclaimer: I work for Nokia, which competes with Google on geographic search.)