"Why not simply let users figure out what THEY want the business model to be. Its similar to how open source companies offer dual licenses for their software. Its available free for personal and recreational use. If you want to build a commercial application on top of it, you pay. Someone wants to run ads in their Twitter client, Twitter should get a cut. Someone wants to sell ad space in their tweets, Twitter should get a cut. Companies want to build applications for brands to mine data and interact with users, Twitter should get a cut. Someone wants to build a paid iPhone app, Twitter should get a cut."

Personal Site of Bryce Roberts