According to TechCrunch, Yahoo has started notifying people if their desired username is available. For users who asked for names that aren’t available now, Yahoo has a solution. They will be keeping wishlists for users for the next 3 years. If those usernames are abandoned and expire, Yahoo will notify people by email.
Any sender using email as an account key (either for resetting passwords or granting access) should be careful about releasing accounts to Yahoo users. Yahoo has established a new header type (Require-recipient-valid-since, currently going through the IETF standards process) to minimize the chance that the wrong people get access to other accounts tied to a recycled mailbox.
For those of us who didn’t put in some addresses we, too, can create username wishlists, we’re just going to pay $1.99 for the privilege.

Yahoo • zombie • zombies