Just happened to me too. There is no better way to piss off your uses than deleting all their email. I could see having a 2 year deactivation, but 4 months? I'm sure the storage space isn't an issue, so this can only be a ploy to try to force users to log in.

Marissa Mayer has her work cut out for her. This, along with probably 10,000 other things, needs to change if Yahoo wants to compete with Google (and Microsoft?).