I think a quick visit to the Super FAQ at the Connect site is in order:
"If the Perpetual Beta is forever, why am I receiving an expiration/cancel notice?
The Perpetual Beta is a perpetual test environment, individual membership is not perpetual. Beta activation keys must be renewed annually. Also the membership of the Perpetual Beta is subject to periodic change and may not coincide with the expiration date of an individual's activation key. Approximately 1 month before your key expires we'll issue you a new key. "
There are instructions on what to do in case of expiration over at the connect site for OneCare. connect.microsoft.com