The Russian investment firm that’s contributed hundreds of millions of dollars to Facebook’s bank accounts is not even close to ending its involvement with social media.  According to Yuri Milner, who’s the CEO and founding partner of Digital Sky Technologies, his organization is interested in doling out another $1 billion.

Obviously, that’s a stunning amount, and perhaps all the more so since Facebook, which is one of the most successful social media sites in existence, doesn’t yet seem to be making money hand over fist.

There’s an aspect of DST’s investment strategy that’s arguably even more interesting, however, as it looks like all – or even most – of the $1 billion isn’t headed for Facebook.  Milner told Olga Kharif, "We monitor close to 50 companies globally that can be potential investment opportunities."

So a significant Facebook backer must think it’s possible for all sorts of other businesses built around social media to turn a profit.  Despite the facts that Twitter’s had so much trouble landing on a revenue model and MySpace may be unable to extend its profitable search deal with Google.

It should be interesting to see how DST proceeds.  Kharif reported that at least one investment should be announced by the middle of this year.