Edit, nevermind, we just entered public beta!
I don't have the feeling we have an issue with (missing) users yet. This is actually an advantage during the private part of the beta stage.
Now we have to focus on:
10 high quality questions per day, to keep content coming
3 high quality answers per question, to keep the answer rate above 2.5 (count: 25 ...
There's also probably a way to ping users who "committed"?
From sidebar of http://area51.stackexchange.com/proposals/89704/ethereum
292 users committed
53.8% signed up for beta
0% fulfilled commitment