To promote the Apple site proposal, I posted the following in a few places. I made some tweaks depending on how familiar I expected the audience to be with Stack Overflow - here's the one I wrote for Reddit:
For those that aren't familiar, Stack Overflow is a site where programmers can get quick answers to their questions. By all measures it's been a rousing success and is now among the top 1000 sites on the internet. There are two sister sites: Server Fault, which covers IT questions, and Super User, which covers general computer hardware and software questions.
The company behind Stack Overflow has recently secured $6 million funding to grow the network, which they are referring to as "Stack Exchange". To accomplish this, there is a mechanism for users to propose sites around certain topics. Since iPhone, iPad, Apple TV, etc. questions aren't allowed on Super User, I've decided to propose an Apple Stack Exchange site. Of course, the site will cover Macs as well.
The proposal process is still in beta, but already the Apple site has gained a bit of traction and is within the top 10% of the sites proposed. The Apple proposal has just moved into the Commitment phase, where prospective users agree to actively participate in the site.
If you are a user of Stack Overflow, or if you just want a place where you can quickly get great answers to your Apple questions, please go to the proposal page and click the "Commit" link. Thanks for your support!
Feel free to use some or all of this for yourself. Of course, you'll want to taylor this to the site you're promoting and the audience you're targeting, but I think it does a good job explaining the basics of Stack Exchange. Also, the $6mm funding isn't really "recent" anymore, and many SE sites have launched successfully, so you may want to mention that.