Six months ago eMarketer estimated that Twitter's 2013 revenue will be about $582 million and 2014 revenue about $1 billion (http://www.emarketer.com/Article/Tw

Six months ago eMarketer estimated that Twitter's 2013 revenue will be about $582 million and 2014 revenue about $1 billion (http://www.emarketer.com/Article/Twitter-Forecast-Up-After-Strong-Mobile-Showing/1009763 http://www.emarketer.com/Article/Twitter-Forecast-Up-After-S...). Facebook's market cap as I write this is $109 billion, and 2014 revenue estimates are ~$11 billion (sorry, I don't have the source for that handy), so it trades at about 10x 2014 revenue. Using this metric would value Twitter at $10 billion. But I expect that Twitter has more room to grow than Facebook since they haven't monetized as heavily yet. I'm guessing Twitter goes out at $15 billion to $20 billion. Disclaimer: I own some Twitter shares, so I'm not objective.