Copying ideas and execution just happens. Look at other industries - there's a Chipotle clone, frozen yogurt clones, etc. And many luxury sedans seem to be about 90% the same design, at least on the outside.

The reason the Samwer story is so weird is a) there's so much damn money in their game (Groupon, Facebook, etc.) and b) they're generally regarded to be ruthless, cut-throat, slave-drivers.

I know I'd feel differently about the phenomenon if they seemed less like idea-pirates and more like contributors to innovation.