I expect a high rate of compliance in early May because members will not be able to post in this thread until their Signature is clean:
http://www.flyertalk.com/forum/ameri...new-rules.html
There is a Signature Review Team which will begin to contact stragglers in mid May.
The whole point of having referral links in signature is to avoid having to post in the Amex thread. I didn't know about that thread until very recently as I rarely venture out of the Aeroplan Alaska and Marriott forums