The Skype revolution few years ago was one of the Internet innovations I was rather unhappy to happen than cool with it.
First of all, my Internet experience was based on technology that didn't allow VoIP communication at all. Hardware was weak, there were no integrated sound devices on motherboards, and the Internet connection usually was slow enough even to load pages properly. That's way my first years were related with IRC and ICQ - more chit-chatting protocols.
The other issue is the closed protocol that Skype provides. Compared to IRC that is open (free-for-all) or ICQ that is at least unlocked at some point, Skype provides no support for 3rd party clients, scripts etc. You have no idea what happens behind the scene. So in fact the only think you have is the facade, the UI that developers have meant for you to use. How does it actually work is an open question for all.
VoIP and video conf calls are great feature to talk to relatives around the world. It's free and it's good to communicate with people abroad and do more 'live' connection with voice and look. But when it comes to business, I would prefer using mails and messaging. First you have enough time to form correctly your thoughts and define it the right way for the other side. Second, you have logging which makes it suitable to keep in touch with what you have to do in a tasklist-like form. The ink is on paper, that's all.
Email/Gtalk is what I would use as an alternative.