updated 02:20 pm EDT, Mon May 16, 2011
Servers failing to respond to pings
The Mail component of MobileMe is currently down or suffering from serious issues, some users are reporting. The exact nature of the trouble can range from difficulty with the web app to IMAP services being unavailable. Pinging mail.me.com may not work, and did not work for MacNN.
In extreme cases it may be impossible to log in at me.com. Apple has yet to provide an explanation for current problems, or a resolution timeline. The MobileMe status page in fact claims that all services are online, although it was last updated at 4:20AM Pacific.
Update: The MobileMe status page has since been updated to reflect the mail issues noted above, but no timetable was given for a fix: "Some MobileMe members may be unable to access MobileMe Mail. Normal service will be restored ASAP. We apologize for any inconvenience."