I found an interesting video about social networks and social applications on facebook, MyYahoo, myspace etc.

FaceBook=Social Networking.

A social network service focuses on the building and verifying of online social networks for communities of people who share interests and activities.

Yesterday, I've created an account on facebook.

They have an Ad Manager application(on the left side of first page). I have created an ad:

I have selected one day period, 5$/day (minimum),

0.10$ per 1000 impresions

and 0.03$ per click.

but they enabled my ad after I changed my bid from 0.10$ to 0.16$ as they sugested.

So after 5 hours of advertising my ad has over 12 000 impresions , cost is over 1.5$ and clicks - only 3

PS: I have changed my bid from 0.16$ to 0.10$ per 1000 impresions and it works. (updates are visible in 15 minutes)