Yesterday's GMail outage marks the sixth downtime in eight months as reported by PCWorld. For businesses that rely on e-mail, a two and a half hour outage is clearly unacceptable. For some companies it's almost as bad as a power cut for two and a half hours. It's one reason that many companies are continuing to host their own mail rather than entrust it to a third party. I'm interested to hear from other businesses on this. How would your business be affected by a two and a half hour outage?