I don't think they really care if they are viable business models - see their investment in a Groupon clone. I think what they are doing is simply copying companies, creating them with the sole purpose of being bought by the company that originated the idea. There's nothing in any of these articles that says they're creating viable businesses (they may have some however). So what they are doing, in my opinion, is similar to what patent trolls do - extract money/stock from VC-rich startups. Wash, rinse, repeat.

It will/would be interesting to see how they do in a down startup environment where the VC money isn't flowing quite so freely.