Google's Gmail online e-mail service ran out of juice for several hours Tuesday morning for users in Europe and possibly worldwide.
British users noticed Gmail conked out around 10:30 local time, or 5:30 a.m. EST, and came back online about 3 hours later.
Reports came in from the U.S. that it had stopped working there as well. Tests in New York at around 7:30 EST revealed intermittent service, with some users able to use Gmail and others not. Mobile Gmail service appeared to be down until about 8:45 a.m. EST.
"We're aware of a problem with Gmail affecting a small subset of users," read a posting at 5:46 a.m. EST in a GMail help forum.
Later, at 8:48 a.m., another post read, "The problem is now resolved and users have had access restored. We know how important Gmail is to our users, so we take issues like this very seriously, and we apologize for the inconvenience."
Some British users reported that they had to fill out a "captcha" form — which makes users prove they're human by deciphering garbled letters — when logging back in, indicating that a virus or automated program may have tried to compromise Gmail.
Twitter predictably went into overdrive, with European users complaining about "Gfail" and a few others taking a longer perspective.
"3 hours without #Gmail. If that means crisis for you, check your reality," wrote a Dutch journalist with the Twitter handle mmarjoleiN. "Dependence is a bitch."
The outage exposed the underlying vulnerability of "cloud" computing, in which applications and data are accessed by users on the Internet instead of their own hard drives.
Google has been trying to sell its cloud-based Google Apps service to businesses for a couple of years, with notable success in getting some companies to switch to Gmail from Microsoft's Outlook.
Microsoft, never one to be left behind, has been promoting its similar Windows Live service.
But there's always one problem with cloud computing. If the central servers, or your Internet access, go down, you're dead in the water, as a few British businesses seem to have found this morning.
Of course, there may have been another reason for the outage, as one wag on Twitter posted.
"When Chuck Norris uses Gmail, the whole world waits until he's done," the posting read — in French.
• Click here to visit the Gmail support homepage for updates.