Here we go again:

Twitter is mulling over raising a new round of financing, we've heard from multiple sources, and a variety of venture firms are frothing at the mouth to lead the round. The valuation is likely to be in the $3 billion range, and they'll likely raise more than the $100 million they took a little over a year ago at a $1 billion valuation. To date Twitter has raised around $160 million.

The company, which began selling advertisements and making money (how novel!) earlier this year, is looking like an increasingly formidable competitor to Google, and maybe even some news organizations, when it comes to real-time search. Which explains the whole "frothing at the mouth" thing. But are they really worth $3 billion? It's hard to say. And as we know, social network valuations are just a little tricky.