How did the VCs perform with the Groupon IPO?

First, they generally can't sell shares for 180 days (the so-called "lockup period"), so where the stock is trading now doesn't indicate much about where it will be in 6 months.

Second, even once the lockup comes off, VCs (and other insiders) won't all necessarily cash out at the same time without causing downward pressure on the stock when it is distributed to their LPs.

Third, in a way, who cares? Most of them were pure dumb money in this case. The majority of big-name investors participated only in the last $950M round in Dec 10/Jan 11, which, as is widely known, went almost entirely into the pocket of management and earlier investors. The new VCs added no value, weren't on the board, and were just along for what they assumed would be a short ride between their investment and IPO. It was a momentum bet, pure and simple. One can certainly make money that way, but I doubt it's how they think of themselves (or when they tell themselves when looking in the mirror). There are times when VCs add lots of value. This wasn't one of them.