From what I've heard, this is EC2's only outage in the past year. Amazon's SLA guarantees 99.95% availability for a region (meaning that if you have 2 instances running in different availability zones, Amazon guarantees that at least one of the instances will be up 99.95% of the time). However, with a 3 hour downtime being their only downtime (so far as I'm aware) in the past year, they're hitting 99.95% uptime
within an availability zone.
It should be noted that the 365 Main datacenter that hosts (hosted?) Craigslist, Six Apart, Technorati, and a number of high profile web companies had a total failure a while back (http://radar.oreilly.com/archives/2007/07/365-main-datace.ht...). Similarly, Rackspace (whose business is not having to worry about your servers) had 3 outages in 2 days (http://gawker.com/tech/followup/rackspace-outage-was-third-i...).
So, Amazon's 3 hour outage that affected a minority of their customers doesn't seem that outrageous. You're totally right. The author was probably writing a bit of link-bait to get read. No one reads "Amazon EC2 has minor outage that compares favorably against their competitors and affected a minority of their customers." That's just business-as-usual talk. However, if you question the entire viability of cloud computing because of a 3 hour outage, well, that deserves reading.