I don't recall a similar email when Yahoo! acquired delicious in the first place, why they should want permission now is beyond me.

Hurley & Chen surely can do a better job and it strikes me as though an 'opt-out' would have been better in this situation, or at least a process that would survive the actual transfer of assets between the two entities.

Yahoo! has a long history of losing their users data through shutdowns (geocities!), to see them lose user data on the spin-out and sale of a company they acquired a few years ago is probably just another 'snafu' for them.