This has been discussed elsewhere:
Online Dating
From my experience and observations, if you are a young heterosexual male, online dating is a waste of your time and you'd be much better off taking up an interesting hobby/joining a local club that enables you to meet like minded people, preferably one with better gender odds. Make sure it's something you'll enjoy. For dating men though (whether as women or gay/bi men), online dating often seems optimal, though I'd still recommend simply going out, having fun, and seeing who you meet in the process.