Skype is still ok to communicate and is widely used.
Just be sure you don't send sensitive information.
Somewhat sensitive information (such as your IP) is sent automatically when Skype is opened. When teaching people how to DDoS, I don't think revealing your IP would be the best course of action.
Ya got me there, but the number of customers who use Skype simply makes it unfeasible to ignore the userbase.
Fair point, though you should at least look into using a proxy with Skype if you aren't already. You can reveal an IP from Singapore right now from your Skype name.
I've never been DDoSed seriously before, and I don't consider it a big enough risk to warrant the hassle. I think a kid tried using LOIC on me once...