Who is living off their startup fulltime?
S3stat (http://www.s3stat.com) brings in enough to live on, and funded me while I was traveling last year and bootstrapping the next thing.  It also has the advantage of pretty much running itself on autopilot, so I can sometimes go entire months without opening the IDE or doing anything beyond responding to the odd customer email.I'd highly recommend building something like that (a low-maintenance income generating business) as opposed to the sort of zero income "shorten urls then tweet them from your location on your camera phone" thing that requires 14 billion users and a Google buyout before you see your first dime.