"We know how many people rely on Gmail for personal and professional communications, and we take it very seriously when there's a problem with the service," said the firm's Ben Treynor in a blog post.
"Thus, right up front, I'd like to apologise to all of you - today's outage was a big deal, and we're treating it as such."
Treynor blamed the outage on a miscalculation by system engineers who had taken some of the services servers offline for maintenance, routing the traffic to other servers which caved under the increased flow of traffic.
If you were like me, the first sign of trouble arrived in the flood of tweets about the incident on Twitter. It was bigger news than a celebrity death! At least amongst those of whom I follow.