I didn't know if anyone had ideas on what are the best ways to get visitors to register. and also what do you put on your home page for social networking sites that intrigue them to sign up.

I'm finding once I have the visitor and they are on the front page, having to register to be active on the site turns them off.

So what are some ideas to have on the front page, for visitors to participate in, that they don't have to register just yet to be apart of?

Any ideas will be of great help, thanks in advance.