I use twitter and facebook to blast out quick announcements with links back to my forum to draw people in. I don't have many followers on twitter yet as most of my membership "just doesn't get it" but my facebook group is growing by about 100 users a month, just passed 800, and it seems to be helping bring more traffic to my site, and the users seem to like the wya I am putting it to use.

"No matter where you go, there you are."
"If you can't do something smart, Do something right"
"There are three kinds of people in the world, those who can count, and those who can't"