Adding onto Nathan's post, it differs from Twitter where you're subscribing to different topics rather than specific users you might follow. It's a lot like a forum like this one where you can discuss just about anything other than the Nationals. Much closer to WNFF than Twitter, in my opinion really. Although you can discuss the Nationals too.
The toughest thing for me starting out was getting used to the comment section, more specifically the indentation of child comments to parent comments. It can be tough to discern at first.
Any way, saltydad, if you have a question for Charlie and Dave you should go there and hit the "Reply" button just before everyone else's comments start, and a box to type your question in will appear. If you need more help just post here.