Microsoft goes out of business???

Social networking: I did not know this, but Microsoft  has(had until July 31) a free classified listing, http://expo.live.com , similar to Craig's  list. But Craig's list has pushed the corporate giant out of the free social  networking-classified business. The irony is Microsoft, with its long history  of swallowing up smaller companies to acquire their technologies and putting  them on the shelf is the Craigslist web site, to push the mega-giant out of a  marketing niche, such as social-networking. 

I think that the Owners of Craig's list (Jim Craig-founder,  Jim Buckmaster-CEO)  know that they are  sitting on a gold-mine, which in 1995 was only a San Fransisco email  listing  of social events in 1995 . The  relatively un-commercial nature of Craigslist has become the world's 8 busiest  english language web site in terms of page views (http://www.craigslist.org/about/factsheet.html).  Yet,  Craigslist incorporated  as a for-profit company in 1999 does not display  advertising and marketing on it's pages. 

So why doesn't Microsoft attempt to buy Craigslist Like  Google bought YouTube and MySpace , or Microsoft's attempt to buy Yahoo? Is  Craigslist too popular among the non-commercial community's community? What do  you think?