Making some people very rich is not the same thing as creating value.

If Groupon investors get rich at the expense of retail investors, that's bad. If the Groupon founders get rich at the expense of retail investors and later venture investors, that's also bad. In fact it's worse, because they have more information about the business than the investors do. The closer you are to the center of the business, the more you are implicated if it turns out to be a giant pump-and-dump scheme. The founders are the rotten core of that scheme.