Pinterest executives got a surprise during last year’s holiday season. Consumers were spending so much time using the online scrapbook that Pinterest’s computing bills on Amazon Web Services—the internet retailer’s cloud offering—had shot past their expectations.

Pinterest, which had paid in advance for AWS’s services, had to buy additional capacity at a higher price. That contributed to Pinterest spending roughly $190 million on AWS last year, $20 million more than it had initially expected, according to a person close to the company and figures seen by The Information.

Pinterest is hardly alone in ending up with a bigger than expected AWS bill, according to an examination of the AWS spending patterns of five large companies conducted by The Information.