I think a lot of people hear "complaining noises" and start a new venue, thinking that the 100 or so gripey users are actually tens of thousands.

Then the reality sets in: Just because someone is complaining doesn't mean they are quite ready to abandon ship. A great exercise is to look at the "new posts" feed for each of these sites... Whaleshares had 11 new posts in the last 30 minutes; Weku had 14... and here we had hundreds.

Yes, Smoke appears to be doing quite well... and they had the wisdom to make themselves a niche site.