Some users of Google's vaunted Google Docs service discovered this weekend that behind their backs the widgetry has been sharing some of their documents with folks who were never authorized to see them.

There are at least three things that might keep a cloud user up at night: fear the cloud will go down at a critical juncture, fear data will be irretrievably lost, and fear of a security breach.

Google claims to have fixed the bug that was first reported to it on February 24.

It also claims that the error was limited to text documents and presentations. Spreadsheets reportedly weren't affected.

And Google Docs product manager Jennifer Mazzon claims on a blog that less than 0.05% of all the documents in Google Docs' custody were impacted.

The Google Docs Team says the glitch only happened "if you, or a collaborator with sharing rights, selected multiple documents and presentations from the documents list and changed the sharing permissions."

Here's the e-mail they circulated:

"Dear Google Docs user,

"We wanted to let you know about a recent issue with your Google Docs account. We've identified and fixed a bug which may have caused you to share some of your documents without your knowledge. This inadvertent sharing was limited to people with whom you, or a collaborator with sharing rights, had previously shared a document. The issue only occurred if you, or a collaborator with sharing rights, selected multiple documents and presentations from the documents list and changed the sharing permissions. This issue affected documents and presentations, but not spreadsheets.

"To help remedy this issue, we have used an automated process to remove collaborators and viewers from the documents that we identified as being affected. Since the impacted documents are now accessible only to you, you will need to re-share the documents manually. For your reference, we've listed below the documents identified as being affected.

"We apologize for the inconvenience that this issue may have caused. We want to assure you that we are treating this issue with the highest priority."