Guess the push to attract more advertisers is getting more emphasis these days. I remember when Overture refused to have referrals - except in Europe (which started its own problems).
Now apparently it is becoming more important.
They are going to copy the Google Qualified Professional approach (even charging the soon to be industry standard $50) and give incentives for the new customer signups - though they will offer $80 referrals for new high-end advertisers sent to them (as was already being done through Commission Junction).
They have also announced an enhanced program for smaller agencies.