I took an off the cuff stab at trying to identify potential revenue streams (here and here)for Twitter as they garnish a large enough user base to monetize. It did not hit me till I had an Epiphany this morning over my morning coffee.
I have always preached that Twitter will be a big thing, a *next generation operating system (OS)*, and when you own an OS (think Microsoft) it is not a far reach to offer new services to your substantial user base.
So in a year from now, though you may not think of it as Twitter, when you read about Twitter's success it will be;
Twitter as the next Monster.com (Job listing board)
Twitter as the next Craigslist (location aware Tweets will be a huge assistance to this)
Twitter as the next Cars.com
See they have BOTH sides to an element of success, a large user base. And an ever growing large database. The ability to mine, and verticalize this database will give Twitter the opportunity to own any market they so desire (listings).
Want to see the first proof? ...and so it starts