This has been an important lesson in single point of failure (which is one of the core reasons I'm always harping on about decentralised services). We use Skype pretty much universally to talk to each other; although alternatives exist, it's the one that almost everybody is almost guaranteed to be on. The alternative is the traditional phone network, which is nowhere near as cost effective.
It's forced us to create a new communication plan, and I'm certain we're not the only tech company in the same boat. The Internet has meant that we can resource people from all over the world; it's no good if we then can't talk to them.
Annoyances aside, my thoughts go out to the Skype team, who probably haven't slept at all in the last day. They're going to be under serious pressure from both their millions of users and their parent company; I hope they work it out and can get some rest soon.
Update: here's a plausible explanation for the mess.
Keywords: communication, outage, single point of failure, skype, skype outage, voip

Comments
I agree with Ben, remarking that there is also a lot of people that stays in touch through skype with their family and dear ones, because it shortens distances between them at zero cost.
Thinking like that means everyone should live in himalaya, drop the job and live into a cave like gauthama buddha and i guess that this is not the case for most of us