Google later apologized for the error, blaming a software bug on the outage, which affected about 10 percent of its users for a little less than an hour. Gmail, Google+, Calendar and Documents were affected, it said.

Users who tried to access Gmail about 11:15 AM PT on Friday received the message at the top of the page: "We’re sorry, but your Gmail account is temporarily unavailable," it read. "We apologize for the inconvenience and suggest trying again in a few minutes."

By 12:23 PM, Google said, it had restored service. "The problem with Gmail should be resolved," the company said. "We apologize for the inconvenience and thank you for your patience and continued support. Please rest assured that system reliability is a top priority at Google, and we are making continuous improvements to make our systems better."

Gmail then referred users to the Google Apps Status Page, which confirmed the outage as of 11:12 AM PT. "We're investigating reports of an issue with Gmail," the message read. "We will provide more information shortly."

Google didn't confirm any problems with Google+ or its other services, but Google+ failed to load anything but the top index for this reporter, generating a "500" error. Google Drive worked normally on one occasion, but failed to load file names and images on a subsequent refresh. YouTube appeared to operate normally.

At press time, it was unknown how many users were affected by the outage. Google's Gmail has gone down before, with multihour outages in 2009 taking down the Webmail service at least eight times in nine months. In April 2012, a lingering Gmail outage that seemingly only affected a small percentage of the user base was confirmed to affect up to 10 percent of its users, which would have affected over 30 million separate accounts.

 Naturally, users too to Twitter to complain, giving voice to comments like the one above. Unfortunately, Yahoo made the decision to tweet -- repeatedly -- that Google's Gmail was unavailable. Late on Friday, Yahoo said that it had deleted the tweet.

 The irony of it all is that when the service failed, Google's site reliability team was in the midst of an "Ask Me Anything" session on Reddit. So far, every question on the AMA was about the Gmail outage—and the team had not responded to a single one.

Meanwhile, TechCrunch reported the bizarre situation of a man who since last night has been receiving a deluge of emails because of a link that appears when people search for “Gmail” on Google.

Such a search query delivers as its first result—as expected—a link for Gmail, but a sub-link that appears below it, labeled “Email” triggers, when clicked upon, a Gmail message interface already addressed to the man’s Hotmail account.

It’s not clear whether this issue is related to the outages on Friday afternoon, since the man, David Peck, told TechCrunch that the issue started on Thursday evening.

Google apologizes

Google apologized for the outage in a blog post on Friday evening.

"Whether the effect was brief or lasted the better part of an hour, please accept our apologies—we strive to make all of Google’s services available and fast for you, all the time, and we missed the mark today," Ben Treynor, Google's vice president of engineering, wrote.

"At 10:55 AM PST, an internal system that generates configurations—essentially, information that tells other systems how to behave—encountered a software bug and generated an incorrect configuration," Treynor wrote. "The incorrect configuration was sent to live services over the next 15 minutes, caused users’ requests for their data to be ignored, and those services, in turn, generated errors." A correct configuration was pushed live by 11:30 AM.

Treynor wrote that Google wold work to correct the bug in the configuration generator, and add additional targeted monitoring to make sure outages like this did not happen again.

Juan Carlos Perez of IDG News Service contributed to this report.

Story updated at 1:29 PM PT to note that Google believes the outage to be resolved.
Story updated at 2:34 PM PT to add more information from IDG News Service. Story updated at 2:43 PM PT to add Yahoo details, and then again at 9:39 PM to add Google's apology.