Launch date: May 27, 2009

Fatal flaw(s): Not enough users, abundance of features 

When Google introduced its next-gen messaging service to an overly enthusiastic I/O event crowd in '09, everyone thought the next great communication platform had arrived. Part instant messenger, part Twitter, part e-mail, Google Wave promised to deliver a new way of collaborating and staying in touch with friends and co-workers. Too bad no one else thought so. A year later, Google pulled the plug on the service that would let you see what your friend was typing in real-time, saying it "has not seen the user adoption we would have liked."