Amazon's cloud infrastructure service, Amazon Web Services (AWS), suffered an outage on Saturday morning leaving many websites inaccessible to users.
Well-known sites such as Netflix, Pinterest and Instagram were among those affected.
According to the New York Times, the datacentre outage was caused by a thunderstorm in Northern Virginia.
Amazon offered little information direct to its customers on the outage, or on the security of users' data. However, updates did appear on its service health dashboard, reinforcing the "self service" aspect of much cloud provision.
Amazon first acknowledged the problem by stating: "We are investigating connectivity issues for a number of instances in the US-EAST-1 Region."
It later said that it was continuing to work to bring the instances and volumes back online and that, in addition, "EC2 and EBS APIs are currently experiencing elevated error rates."
Amazon customers took to Twitter to ask the cloud computing service for help. Amazon responded by referring them to its "Contact us" page.
One tweet from a disgruntled customer said: "#AWS status dashboard seems to report issues precisely 35 minutes after they start. 5 minutes to write + 30 min to get lawyer approval."
About six hours later, the service health dashboard said: "The service is now operating normally. We will post back here with an update once we have details on the root cause analysis."
The outage underlines recent Computing research*, which has shown that over half (51 per cent) of IT decision-makers are concerned that there is a growing dependency on connectivity. Loss of control was cited as another key concern (55 per cent of IT decision-makers) with hosted services.
Last year, Computing's research** found that only eight per cent of IT decision-makers had opted to deploy a public cloud, with the majority of respondents implementing a hybrid solution, in which some applications are migrated to the cloud and others still run in on-premise datacentres.
The hit to AWS's services comes at a time when Google has announced that it is looking to offer a package to rival Amazon with its Compute Engine product, an infrastructure-as-a-service (IaaS) cloud platform that allows it to build applications and websites, plus store and analyse data on Google's infrastructure.
*Computing research of 100 IT decision-makers at UK SMEs, March 2012
**Last year's Computing research was of 172 IT decision-makers in enterprises, July 2011
• The outage follows a similar incident on 14 June and has angered AWS customers, with one customer publicly announcing that it will cease to use Amazon EC2 and switch to another provider instead.