Maybe further evidence that this is not, in fact, "scheduled maintenance". I checked my emails, Apple has notified me before when they were planning something, although specifically for iTunes Connect. Why not this time? The sites affected are no less important to a developer than iTunes Connect. And come to think of it, I don't remember the other sites (like the developer forums) ever being down.
iTunes Connect will be undergoing scheduled maintenance on Monday, February 13 from 7 p.m. to 12 a.m. PDT.
iTunes Connect will be undergoing scheduled maintenance on Thursday, October 25 from 12 p.m. to 7 p.m. (Pacific).
iTunes Connect will undergo scheduled maintenance for approximately four hours starting at 8 p.m. (PT) on Saturday, January 26.
iTunes Connect will undergo scheduled maintenance for approximately one hour starting at 11 p.m. (PT) on Tuesday, June 25, 2013.