Specifically 60 people's entire inboxes form GMail. This is probably a minor incident, and something that Google will be able to resolve very easily. However, they haven't said what exactly went wrong.
This is one of those stories that can either be blown out of all proportion or can disappear very fast indeed. I think this is something worth monitoring to see what happens!
I think Google are generally good at PR, so my money's on this little story disappearing.