Clarification: Don't reinvent the wheel means Don't exactly copy another product. It's damn important to reinvent defensible products that either, and hopefully do all of:

a) solve a slightly different problem

b) target different users

c) solve the problem in a 10x better, compelling way

Uniqueness will be added to the collective, so don't bother creating categories because that requires extra effort building validation from below zero and any new products coming along can execute much easier with the lessons and improvements of the "settlers."