Amazon Web Services' cloud-computing infrastructure experienced a brief network outage this evening that knocked offline popular sites such as Netflix, Quora, Reddit, and Foursquare.

The network connectivity issues struck Amazon's Elastic Compute Cloud (EC2) at Amazon's northern Virginia site, which handles AWS operations for the U.S. East Coast at 7:39 p.m. PDT and were resolved about 25 minutes later, according to the Amazon Web Services Health Dashboard.

AWS is a flagship example of one facet of cloud computing, a flexible collection of online computing services that can ramp up and down according to varying needs, with customers getting a flexible infrastructure and paying only for what they consume.

At the same time, though, when a widely used service goes down, many suffer. In April, the cloud storage service experienced a two-day outage that brought many Web site operations to a halt.

Amazon representatives did not immediately respond to a request for comment.