That means some Web sites were down or partially disabled for at least 11 hours.

While that's a problem for the downed sites, it's probably going to be tougher on Amazon itself, according to Robert Mahowald, an analyst with IDC. "Amazon is held as a paradigm of operational uptime," he said. "When this kind of thing happens, it definitely sends a chill through the whole cloud and hosted services industry.... It's absolutely a black eye. There's no doubt about it."

Mahowald was quick to point out that this kind of outage happens. It doesn't point to a specific operational problem at Amazon.

"This shouldn't give Amazon a bad reputation, but this is a very, very visible problem," he said. "I don't think it will turn people's heads away from using Amazon, but it will give companies that have been on the fence a lot of cause for pause. This will live on and on on the Web."

The biggest impact from the outage may be to the cloud itself, said Rob Enderle, an analyst with the Enderle Group.