viral/referral online sites

[bruce]

Hey peeps...

Has anyone used any of the online services to setup/run viral/growth campaigns?

I'm thinking of sites like launchrock, viral-loops, kickofflabs, etc..

I'm looking to generate a prelaunch/viral/kickstarter kind of process
to create an initial community where users refer other users etc.. I'd
really like to use an existing service and pay the fee if it gets the
project where it needs to be.

Rolling my own would be a longshot option.

Thoughts/comments welcome.

thanks

-bruce