Go to this page on the Microsoft downloads area and then download the file which is the Exchange Hosted Services Service Level Agreement document.

Scroll down to the bottom, and you will find what Microsoft will pay you if they fall foul of the SLA.

Basically, they will give you “Service Credits” for downtime, and at no point will the Credit exceed the value of what you pay Microsoft for the month of service provision.

Now look at the percentages: to get 100% of your money back, Microsoft has to fail a 95% SLA.

For the sake of easy Maths, let’s assume there are 30 days in a month, which equals 720 hours. 95% uptime is 36 hours over the entire month. 36 hours is 4.5 working days of downtime, assuming an 8-hour work day.

So the most you can get back from Microsoft only kicks in when you have had your hosted exchange server down for almost one week in four, assuming all the unexpected downtime happens within your working day. Hardly generous, is it?

But there’s more: “Scheduled downtime” is excluded from this rebate scheme until it exceeds another 10 hours per calendar month.

Quite apart from this, the document is a wonderful example of legalese and obfuscation. How about this part:

“‘Monthly Uptime Percentage’ for a specific Customer is calculated by taking the total number of minutes in a calendar month multiplied by the total number of licensed users minus the total number of minutes of Downtime experienced by all users in a given calendar month, all divided by the total number of minutes in that calendar month multiplied by the total number of users.”

Well that’s perfectly clear then.

By the way, it’s the same terms for the hosted SharePoint and hosted Live Meeting too. And of course, there is no link between these SLAs either, as far as I can see.