I was in Cyprus recently and noticed on several occasions that Internet performance was a bit flakey. It was often very fast, but every 15 minutes or so would grind to a halt for a couple of minutes. I was about to complain to the hotel when I noticed a report on the BBC website about a large DDoS attack. It seems that the attacker was mainly trying to take down DNS, but I think I was affected by the collateral damage:
http://www.bbc.co.uk/news/technology-21954636
Now corporations are using the Internet much more for business critical applications, I do wonder just how robust the Internet actually is and how long before there's a really serious Internet outage that makes them rethink their Cloud strategies.