How we lost revenue by improving our signup process

"When our 4 week experiment ended, we immediately reverted to our previous signup process. We subsequently had our largest month’s growth, ever."

Maybe brief periods of unrestricted signups create enough buzz to boost revenue over the long-term?

Wonder how this dynamic plays out in SaaS products that have network effects. For example in a B2B communication service (like ours) you want users (in one signed-up account) to be able to communicate with other users (who have not signed up) and not have THOSE users have to pull out THEIR credit cards since they were not making an explicit decision to join.

We've settled on 3 free users in a business account to facilitate this viral effect. (3 being the smallest group greater than a pair :). Wonder if anyone has any thoughts on this?

Will update you on our experiences as we are launching soon.