On the other hand, most places don't need that level of reliablity. If a company email server went down for a few hours it's not that big a deal. Even for most large corps, only a certain few things need that level of reliability.

I often see it get written into contracts with very little thought as to what it means. You get some great looks from managment when you break the figure down into minutes though, especially when you don't have 24/7 staffing. A poorly timed cosmic ray could ruin your SLA.

* It would where I'm at now, because someone thought it would be a good idea to handle a critical business process by emails csv's.