[lominming]

Let's just imagine the one-liner of the big companies today: - Google: Yahoo with PageRank - Facebook: Friendster for colleges - Dropbox: Files sharing made easy - Yelp: User reviews for restaurants

All ideas seem small and narrow at the start. It is true that you should recognize the possible direction the startup could go, but as PG said before, it is important to first make something that a group of users really really love. From there, you start growing into something bigger. The main point is that you may not know what it will grow and evolve to when you first start the company.