Kazaa did not contain spyware/malware until it was bought by Sharman Networks. Skype is a very well made program. Can you use Roger Wilco to call a landline? Can you get a phone number assigned to Roger Wilco and call someone on their computer? How about popping into chat mode and sending a file or url?
You don't have to love them or use their products, but IMO they have been putting out some very good, easy to use products and deserve some credit for innovative ideas, and their ability to take those ideas and turn them into a really smooth piece of tech.