Last night, Amazon's EC2 web-hosting service suffered a technical problem that took down some of web's biggest social media sites. While most people think of Amazon as the world's biggest online retailer it's also the world's biggest cloud-computing provider. So when its servers went down, it took Reddit, Foursquare, Quora and Hootsuite down with it*. The reason so many sites choose Amazon is because its hosting fees are some of the cheapest around. Many, if not most, companies rely on third parties to run their servers. But the proliferation of companies relying on Amazon's hosting service shows how a hiccup can turn into a storm. 

"On the plus side, it lets startups scale up their infrastructure much more cheaply and inefficiently," writes Business Insider's Pascal-Emmanuel Gobry. "On the down side, they have to rely on an outside party for the most crucial part of their service -- staying up. Even the best, and Amazon is widely considered to be one of the best, will have an outage like this once in a while."

Jacob Aron at the New Scientist notes that as the web hosting industry becomes more consolidated it holds major risks for the Internet's independence. "Is there a danger in placing too much of the web on Amazon's servers? The company has already shown its willingness to get rid of problematic sites, as demonstrated by the removal of WikiLeaks from its servers in December last year," he writes. "The internet was designed as a distributed network that could route around failure, but the web is now becoming increasingly centralised as more services move in to the cloud." He also notes that Amazon has just revealed itself as major target for malicious hackers. "With some of the web's big names inaccessible, it's now clear that Amazon is a target for those looking to cause major online disruption," he writes.

*Update: The server crash has disrupted many more sites than earlier reported. Arik Hesseldahl at All Things D has a running list that includes: location-based gaming platform SCVNGR, iPad music app Discovr, social media app Wildfir, real-time comments start-up Livefyre, software company CampgroundManager.com, customer-relations company Totango, Canadian-based employee scheduling service ESchedule, web host ZeHosting, analytics engine Recorded Future, mobile analytics firm PercentMobile and application hosting service The Cydia Store