Ashish Dixit from San Francisco created a Facebook application called (Lil) Green Patch that has been valued by Adonomics as worth $4,367,160.

The application has over 10 million users in total with 10% active userbase.

I don't know what Adonomics bases their valuations on but that's pretty impressive for something that was create only a year ago.

Here is the info.

http://adonomics.com/developer/709042250