Being Free to join, attracting people to join is not a big issue. We all are getting large no. of affiliates daily.
Actual work begun after joining. It's a tough job to get those new members going.
Every methods ,such as PSA Reassignment, TCredit transfer or some other methods know to us work's to motivate them to start moving.
Apart all this methods , best way to convince people is communication in regular interval.I try to create a relation with my PSA's and create a friendly atmosphere by not always talking about SFI ,but sharing other parts of life also.