How do I build a comunity for my forum?

I Just launched a classifieds forum and want to know how to rapidly get membert to join.

 

I read something on your signature, try that..

 

The easiest way is to have a website related to your forum.

If you don't have an already established website,
the faster way is to invest in Adwords or Adcenter to get the first 1000 ads.
With 500$ or less, this should be done easily.