Apple's 'Unexpected' Developer Portal Maintenance Seems To Indicate Hackery
It should be stated that this is in no way confirmed, but tweets are surfacing nearly every minute that suggest tons of attempts were made to change one's User ID / password. Apple hit a similar hiccup earlier in the year, and then went on to institute (optional) two-factor verification for accounts.
If you're an Apple developer, now would be an excellent time to reset your password. It's not clear that anything fishy is ongoing, but better safe than sorry -- right?