Twitter is two years old now, but they don’t seem to have a solid revenue model to generate profits out of their fast growing microblogging service. They turned down offer a $500 million acquisition deal from Facebook and they aren’t interested in ad-based revenue model like most web startups.
In an interview with Reuters, Twitter co-founder, Biz Stone, acknowledges that Twitter’s rapid growth cannot last forever. He said that his company is working on a revenue stream by building paid add-ons or services for professional or business users of Twitter.
"Twitter would remain free for consumers and businesses, and that the company’s main focus at the moment is developing new features for commercial users, such as "lightweight analytics" and a directory of commercial accounts that would verify that businesses on Twitter are legitimate"
Twitter can also strike a revenue sharing deals with cellphone carriers to make Twitter work on cellular network. I’ve read stories about how local business profited by using Twitter. Twitter’s upcoming revenue model seems reasonable enough!