I would never want the IDEA of pinterest to be protected, but pinspire's name, branding and service are so strikingly similar that it will undoubtedly cause confusion among potential customers. That should be illegal, and I imagine that it already is to some degree; I know for a fact that if I started coka cola soda company tomorrow I would probably have a cease and desist letter on my doorstep the very next day. I don't know the law but there has to be some recourse in cases as extreme as this...

Allowing companies to exactly clone other companies is not necessarily good for the market, and I tend to think it's a net negative, especially if it has a chilling effect on innovation.

For an example - at one point in the past, I thought about making a Facebook game, but then I thought "If it succeeds, Zynga will just clone it immediately and pour millions of dollars into marketing theirs, making mine seem like the knockoff". So, I said screw that and I started something else that wasn't a Facebook game. In this case, this sort of effect helps Zynga develop a monopoly.

In making something, making the right set of design decisions is vastly harder than implementing it once those decisions are made. Back when implementation was also extremely difficult, this was probably less of a problem, but now that you can outsource your infrastructure, this is potentially a very real problem.