"People come back to places that send them away."
It's the basic trust proposition of the Internet. People will only trust a service that gives them complete freedom to come and go as they please. Further, they'll want to come back if you send them to cool places. It's why people like Facebook today, and why they'll be tired of it tomorrow, if it only sends you to places within the Facebook silo.
Dave Winer, "Lock-in and the web, day 2," Scripting News, 3 Aug 2007, www.scripting.com/2007/08/03.html.
