An easy way to leverage social networking is by using twitter, it is easy to get many followers and you can post mini-ads as well as distribute useful content...I use it all the time...
Stephen, I've found that outsourcing your social network building is a good investment, because it is so time consuming, and there are plenty of overseas VA's who will post on social networks all day for $3-$4 an hour!
In fact, I'm looking for someone to split the time adn cost of a full time VA if anyone reading this is interested, get in contact...
Thanks,
Kacey