Earlier this week, Google sent me the following email [extract only].
We wanted to inform you that we are planning to conduct routine maintenance to Google Calendar between 8AM and 9PM on Thursday, April 26th, 2007 .
I asked myself when is the last time Microsoft said that Outlook would have a 13 hour maintenance outage. Now, I don't use Outlook, but I can't imagine big corporations viewing Google's planned outage email and not locking into Outlook and Exchange for another 5 years.
I agree though that this is the cost of hosted services.
At the same time there are very few Exchange systems in the world that can claim 0 down time during a year (I'd bet on there being 0 installs of Exchange that have 0 downtime in 365 days.)
With updates, upgrades and patches you can be sure sometime during the year your Exchange administrator will email everyone and say "Email and calendaring is going to be down this weekend."
Randy
Scott
techlifeweb.com