Is this plagiarism or competition?
dpifke: Rather than agonize over the similarity between the sites, is there a way to differentiate yours?  Doing an exercise like the strategy maps in "Blue Ocean Strategy" comes to mind as something that might be worthwhile.Features != user experience.  Two sites can have exactly the same feature set but their value and popularity can be determined by completely different factors.I should also note that you have a huge opportunity here: if his/your feature sets are that similar, you can observe how folks are using those features before even launching.  You've essentially gotten some free market research with which to refine your product before you have a userbase to complain about changes.