I think everyone knows it.I wanted to hear what othes think about it.
Personally i hate it and don't know why its so popular.Its and easy IM only with built in voice messaging.
I hate that it use screename instead of phone number.Hate it's design which is more like a IM.

Skype needs some stability and performance improvements, but I use it a lot.
I use it to call my folks on video (I know other IM's support this too), and more importantly to call people's home numbers. It is now free in the U.S. to make calls anywhere in the country, and international calls (my wife is French) are cheap too.
For your average computer-to-computer caller, MSN would probably be a better solution though.

But Skype has really caught on, hasn't it? Now there are even businesses using Skype as their phone service.