If you're in the middle of transitioning away from Yahoo either because of its ties with BT or all that business about hacking, it's about to get a little harder -- the company has decided to stop letting users auto-forward messages to alternative accounts. Seemingly to just make it hard for people to leave.
Users of Yahoo Mail found the option had disappeared in early October, and it really does seem to have been orchestrated as a response to the mass hacking revelations, as the automatic forwarding option still works for people who have previously enabled it -- it's just been removed for anyone trying to seamlessly transition their email universe to another provider today.
Yahoo has added a generic statement to its help pages explaining the problem, which says: "This feature is under development. While we work to improve it, we’ve temporarily disabled the ability to turn on Mail Forwarding for new forwarding addresses. If you’ve already enabled Mail Forwarding in the past, your email will continue to forward to the address you previously configured."