Cribbage - I don't play the game myself but there must be a following, how big or small I do not know. That, of course, is where you need to market it. Hitting a vertical market here so much has to depend on how you intend to develop it.
Started - has a much wider variety of applications as well as a wider spectrum of market, but can be more challenging because of that. Can be used as a news site reporting on the "starting" point for a number of projects, eg. Think and one may be able to develop this into something.
