Yes, you can do this now! You should be doing this now.
On the front page of this Q&A, you will see this form:
That will send the introductory email to any colleague you feel can help build this site. Or you can just post a link to this site if you know a community who can help (the private beta wall is easy to "pass").
You may have noticed a non-trivial slowdown in the number of questions being posted to this site. Nothing concerning at this time, but folks simply run out of questions to ask organically.
The cure for that is you need more users.
But a quick note of caution — before you hop over to the home page to start brainstorming a bunch of questions you can ask just to "hit the numbers", please read the post below and heed the merits of expanding this limited private beta before flooding the home page with forced, semi-contrived questions.
Is user diversity important?