It adds a cost to creating a user account. Sometimes, you actually want that. Also a user with a valid email address is worth more than a user without one; even with dropoff the value could be worth it.
That said, we don't do it at Justin.tv, and I think it's stupid.
You would know much better than me, but I thought the double confirmation process helped prevent emails from the website (e.g. Justin.TV) from getting flagged by spam filters. Have you guys had any problems with this?
That said, we don't do it at Justin.tv, and I think it's stupid.