Screenshot of Amazon's Cloud Drive.
Screenshot of Amazon's Cloud Drive. - 
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Kai Ryssdal: If you've been trying to comment on stories on the New York Times website the past 24 hours or so, you might have run into some trouble. That's because the Times -- along with dozens of other companies -- hosts at least part of its website on cloud services run by Amazon. Works fine, most of the time. But when there's an hiccup, like there's been this week, those companies can't do much but hope Amazon can get them back online quickly. And that dependence, as Marketplace's Jennifer Collins reports, can be costly.

Jennifer Collins: The list of websites hit by this outage includes: Foursquare, ProPublica, HootSuite. George Hamilton of the Yankee Group says it was bound to happen.

George Hamilton: Amazon is the biggest out there. They are the cloud computing thought leader.

He estimates Amazon controls about 5 percent of the market. As many as a third of all large companies use the cloud. Amazon has been pitching the reliability of its data centers. Hamilton says they contain something like watertight compartments on a ship, except...

Hamiliton: Yep, sank the Titantic for 24 hours.

Not all of Amazon's customers sank. Netflix runs on Amazon, and it didn't go down. Neither did the cloud-based software start-up Vocado. CEO Fadi Chehade says he still thinks Amazon is reliable; more important, it's cheap.

Fadi Chehade: We were one of the early users of the Amazon cloud. I think our costs per month were under $1,000. I mean we spent more money on lunches.

It would have cost him hundreds of thousands to buy and maintain servers on his own. But Chehade says he's paid extra for those failsafes that protected his system. And he expects more companies to do so in the future.

I'm Jennifer Collins for Marketplace.