Why gmail went down for the afternoon of Sept 1

Gmail is a fantastic service. Even better than gmail though, is gmail on your own domain name. I work with about a dozen domains with mail hosted on gmail. When they all suddenly went down yesterday it was a big deal to me. That is a lot of users wondering why their mail won’t load.
Google answered the question of why soon after the 100 minute outage was repaired. As it turns out, they were in the midst of a hardware upgrade and did not realize that the load on gmail was as high as it is. While the servers were all able to handle the issue, the routers handling the traffic management were overloaded. IMAP and POP service was available, but outlook sync and web access were down. Google talk and and other apps were up as well.
My response to google: durring my workday, you have been down for a little more than 2 hours in the 5 years that I have been using gmail. Good work! Kudos on constantly upgrading services and servers. Not having to host mail on normal servers makes it all worthwhile.