Join as many as you can but first..

Create two seperate emails account, one will be your 'contact' account, the other will be your 'list' email account. This way your main account will not get swamped with emails. If you can get an yuhknow email which are designed to handle a large volume, especially if you have auto blasters. Join as many safelists as you can.


Safe List Builder
http://www.safelistbuilder.com/index.asp

Join Traffichoopla for free to see what sites they recommend:
http://traffichoopla.com/cgi-bin/ref.cgi/46077/

Traffic Swarm
Ranked #1 by Website Magazine
http://www.trafficswarm.com/go.cgi?634542