The key to making a craigslist competitor is to take away the painful parts and the embarassing parts:<p>1. Carrying your old school monitor to the post office to send it<p>2. Meeting people face-to-face and that uncomfortable stilted conversation.<p>Solve those two problems.
I'm curious, has any company (IT or otherwise) ever beaten an incumbent with a long headstart & network effects <i>by creating their own walled garden</i>? I can't think of any, but surely there must be one.