Outage Knocks Gmail Offline For Many Users
Found on Slashdot on Monday, 23 February 2009

Many readers noted an outage affecting Google's gmail service last night.
"Of course, gmail is just one of the many providers of web-based e-mails. When I look around, almost everyone seems to be using them nowadays. So - what do you do? Do you trust that the site of your web-based e-mail provider will never go down? Do you make backups of all your e-mails?"
What goes up, must come down. Assuming that a service, no matter if free or paid, will run infinitely is, carefully put, stupid. That's why you should avoid proprietary formats which will leave your data useless if the only application that can read them goes belly up. And don't entrust someone else your responsibility of backing up your data. If the data is important, then handle it correctly and make backups.