Because some of the private betas are not active enough, it would be nice to talk about promoting our site.
Do you have any interesting proposals?
Graduated sites have a post on their meta, the community-ads post, in which they accept submissions for adverts for community projects, or relevant things. That includes other sites.
When we enter public beta, we should create a meta thread here inviting submissions for ads promoting this site. When an ad there reaches a vote threshold (we used 6 on Open Source), we can post the ad on another site.
We can also post these ads on related sites around the 'Net.
In private beta, there's a box on the right hand sidebar which lets you invite people. If you know of someone who's interested in this topic, use it. Invite them, and ask them to invite anyone they know of too.
I'm not sure we should be trying to promote the site widely in private beta - private beta is meant to be a time when we figure out our scope and policies, before letting the masses in. If you know of experts that would help the site while it's in private beta, send them an invitation with the box in the sidebar.
However, once we're out of that stage, I'd say Software Recommendations and Super User would be a good place to start. Super User has community promotion ads which we can take advantage of. If/when Software Recommendations graudates, it will have the same thing. Software Recommendations has now graduated, and we now have community promotion ads. Have at it!
Send private beta invites to some of your more technically-oriented friends, family, and acquaintances.