Per this blog entry on beta sites:
The simple answer is, it takes as long as it takes. We’ll wait. If a site needs more activity, go out and evangelize it. As long as your site shows steady progress and continues to make the Internet a better place to get expert answers to your questions, it will march on.
The sites that got closed were, to my understanding, just not performing well across several metrics. Our metrics are pretty good in most areas, only really falling short in questions/day, "avid users", and meta participation (in my opinion).
The Stackexchange team has said before that they will try to give more notice to sites before they really get in danger of being closed down, but also that we'd be able to tell before they even had to step in.
I don't believe we're in immediate danger of being shut down, but we do need to improve. To do that, the most important things we need to do are:
- Keep asking questions!
- Tell your friends about our site
- Vote, vote, and vote!
- Stay active here on meta as well as the main site