I think it means, at the point in TIME when they became a groupon copy they where already past the "startup" phase.

Not that they stopped being a startup because they copied groupon

Crazy to see the downvote mafia around here on this kind of thing.

Hmm, you may be right. Definitely not how I read it at first.

In any event, I think they were a startup at that point in time, but I can see how reasonable people might disagree.