What always struck me about Groupon is nothing to do about vendor complaints. If that was going to kill them it would have manifested as failing demand. It's a kind of no one goes there, too crowded argument.<p>The problem was/is almost the opposite, competition. I never saw, understood Groupons sustainable competitive advantage, especially in new markets/cities. They're obviously competent, but they are <i>so</i> easy to copy. $10k site, $100k ad campaign, 3 salespeople and you have a Groupon clone ready to compete in any city. We have a Groupon clone in the building I work in.<p>Anyway (getting to the actual content of this article), GRPN & FB seem to have something in common, at least to the extent that this article is correct. By IPO time all the value was already taken off the table.