The most important thing you should note is that there are no official beta keys. Blizzard opens the gates to their betas by granting access to your account — not sending you a beta key. If you’re in the beta, you’ll be able to download and play the WoW Classic client from your Battle.net launcher. If not, you aren’t in the beta. It’s easy to be tricked into thinking you’ll get a beta key from an email that looks like it’s from an official Blizzard address, but don’t believe their lies — they’re all fake.
Along with revealing the WoW Classic release date, Blizzard also listed plans for both a beta and stress test of the game. Players who opt-in for the testing on their account manager page and have an active subscription will be randomly selected for the beta starting May 15. Then the developer will have three stress tests where players can log in to play the game for a short period of time on the following dates:
The argument for this is simple: what makes classic WoW great to one player might be different from what makes it great for another. And who are Blizzard's designers to say which old features were just good or bad design for each player? It's an approach that shows Blizzard believes (at least to some degree) that WoW doesn't just belong to its creators but to its fans. That struggle between authorial intent or game design orthodoxy and "the player is always right" is at the heart of many of gaming's big contemporary controversies. But so far, Blizzard seems committed to its plan with regard to WoW Classic.