1. Amazon.com
'Excellent' rating: 50.4% Reuters

Two days after Amazon's cloud computing service was taken down, company engineers are reporting that things are starting to look up.

We're starting to see more meaningful progress in restoring volumes (many have been restored in the last few hours) and expect this progress to continue over the next few hours, Amazon wrote this morning.

Amazon's current issues center on its data center in Northern Virginia. The outage, which first cropped up overnight on Wednesday, disrupted services to many websites including FourSquare and Quora, and Reddit.

As of Friday afternoon, service to Quora and Foursquare has finally been restored, while the social news site Reddit has slowly reinstated complete access to its services.

The outage is a rare one for Amazon, which has historically faced few problems. But the company was clearly not prepared for an outage with the scale of the one that struck its services this week.

There is no word on what caused the initial problems, but Amazon says that the issues started when its systems began creating too many backups.