Gmail, which recently passed AOL to become the third largest Web mail service in the U.S., is obviously having some growing pains. A few hours of downtime is not the end of the world, although it might seem like it at the time. It just better not make this a new habit.
The main issue is that Google obviously has to go down less often. But it's never going to be perfect, that's reserved for God. So the question is how often can it go down without people getting angry? It isn't as if not-cloud applications don't fail, we all know of many instances when computers won't boot up, applications won't work where restores, reinstalls and replacements are necessary. That's why many people have external hard drives which they use to back up their data. It seems the bigger issue is synchronicity and synergy*. If your computer at the office is having issues, others might be doing fine. On the other hand, if everyone at the office is using Google apps then a failure might render the whole office inoperable. One long-term dynamic will be that as Google gets more popular and widespread, the less frequent these outages have to become. Otherwise, Google apps might end up in the Dilbert strip. * I don't mean synergy in a good way. Rather, if/when Google goes down in a Google dependent office that's something you can talk about as a shared experience around the cooler as you wait for the apps to come back online.