Just a valid point to make: Social Connect can post the threads you create to Twitter and/or Facebook to your own Twitter and/or Facebook account. If you wanted it to post the threads your members create to your site's Twitter and Facebook, then my add-on doesn't do that.
You can use Google's Feedburner to publish new posts from a particular forum to twitter. Just add the forum feed then use the publicize option. I guess you could set this up for each forum you want to tweet new posts from.