Cloud failures can occur even to the largest technology companies -- and for seemingly mundane reasons. In 2012, some Microsoft Office 365 customers fell victim to two outages that disrupted the e-mail service for hours at a time.
Microsoft explained the outages in a lengthy blog post and issued credits to customers. In one instance, sluggish antivirus software gummed up the delivery of all kinds of e-mail, not just viruses. In the second case, planned maintenance to Microsoft's data centers and a spike in users trying to access their e-mail caused significant delays.
Special Report: Cybersecurity in the Cloud