A Google ad server went down Wednesday morning, leaving many websites without advertising. Sites like Computerworld and CNBC.com were affected.

The ad server, known as DoubleClick for Publishers, is an advertisement software-as-a-service application.

"DoubleClick for Publishers experienced an outage this morning impacting publishers globally, across their video, display, native and mobile formats," Google said in an email to Comuterworld. "Our team has worked quickly to fix the software bug and [DoubleClick for Publishers] is now back up and running, so our publisher partners can return to funding their content."

According to multiple accounts, the ad server was down for about an hour.

Dan Olds, an analyst with The Gabriel Consulting Group, said the outage likely cost companies across the world millions of dollars.

""First of all, I'm very surprised that Google's DoubleClick service could go down so completely and for so long. This service is Google's cash cow, with huge revenue and high margins," he added. ""This outage won't be devastating to any particular company or set of companies, but it's a shot to Google's reputation and I'm sure that some companies will be looking to see if they have any recourse."

The failure, though short lived, could cause a lot of pain for any company that was launching new products or running specific sales this morning.