Let's find bug

http://www.itechmax.com/2010/07/23/google-also-paying-users-3000-for-identifying-bugs/

http://www.itechmax.com/2010/07/17/mozilla-paying-users-3000-for-finding-bugs/

What a good tactic of encourage people to use your software by this. The software need to be quite stable, or the company will bankrupt :p