Well, Bethany, I'm so glad you asked :)
Let me start with the question "what kind of questions should I be asking?". My take on that is that it's probably best to not hesitate in asking any kind of question (within the context of a community-oriented digital humanities forum – I'm not sure it's the best venue for, say, advice on choosing a school in your local area:).
The hardest thing to judge may be the scope of questions: is it too trivial or technical? is it too broad or theoretical? Personally, I think anything goes. Let the forum community decide how much time and energy is warranted – if you have a question, ask it.
For people with questions, I think there are two main uses for the site:
1) searching/browsing for answers on previously asked questions
2) asking a new question and hopefully getting an answer (or more) fairly quickly
Getting answers quickly was a major part of the design of the site, and in particular the twitter integration. When you post a new question it gets tweeted under the site's own twitter account (not necessarily your own, though you can do that too). We anticipate that there will be a good number of followers of the twitter account and that the question will be seen and addressed in a timely manner.
I think the best way to view this site is as crowd-sourced digital humanities expertise!