Depends how much they add.  Like most people, I think, I don't have a high opinion of things that could be described as knockoffs.  E.g.<p><a href="http://money.cnn.com/2007/10/02/technology/kopy_kat_kids.biz2/index.htm" rel="nofollow">http://money.cnn.com/2007/10/02/technology/kopy_kat_kids.biz...</a><p>Whereas if the idea is significantly transformed, it starts to be a new idea.  If someone started a YC-style operation for funding films, I'd think that was cool.  In fact I've suggested it to several people.