Fake Emails

Recently I've been receiving emails that go directly into my yahoo spam filter. In the past I could tell these were fake emails because it came from an address with @wowaccountadmin.com or something silly. I'm a little worried lately though because I can't use the address to tell it's fake anymore. I just received an email from "[email protected]" asking me to opt into beta. Usually when I hit reply I see the real fake email but it still has the same address. I'm pretty certain it's fake because 1) I already opted in, 2) the link is to "Cataclysmassistance.com", 3) it doesn't have to usual blue background and stuff and looks rather simple format.

It doesn't have the usual bad english/grammar either.

I'm just wondering how am I supposed to know if I get a real beta key if I can't even tell by the sender's address anymore. Can phishers fake a @blizzard.com account now or have I just been deleting real blizzard emails? I looked at the sticky int his forum but it seems out of date to the current techniques.

Thanks

edit: ok so there was another sticky to tell if you are active for the beta, but it's still unnerving receiving an email that says @blizzard.com how can they fake this?