"The terms of service are bad, but even worse is that Google has made clear it will change its terms of service whenever it wishes," said Marc Rotenberg, executive director of the Electronic Privacy Information Center (EPIC).

On March 1, Google "ignored the views of users" and all of its terms of service, Rotenberg said, so that it could "do more data profiling."

"After the unilateral , I don't understand why users would trust Google to stand by its terms of service," he said.

Rotenberg is not alone in his concerns.

Users commenting in online forums said privacy was the reason they would not use Google Drive.