Wow... while surfing wikipedia for yellow pages, I found Wikicompany [[ * Semantical annotations will allow people (or machines) to do graph based queries on Wikicompany information. The Geo extension to geo-code company locations, and to find nearby companies. * ]] -- http://wikicompany.org/wiki/Main_Page
I wonder if there's any way they could get a critical mass of data in there, such that they'd compete with, say, yp.yahoo.com. It seems to me that the market should do better than the volunteer community in this case.