I think then, when we started receiving the first of the user feedback, feedback from people that I had not specifically told about it, but had spread from friend to friend and then they were giving us feedback.
I think the most difficult thing had been scaling the infrastructure. Trying to support the response we had received from our users and the number of people that were interested in using the software.
I think it`s pretty obvious to most people that Napster is not media specific, but I could see a system like Napster evolving into something that allows users to locate and retrieve different types of data other than just MP3s or audio files.
I had to actually purchase a book to learn the API and write the client. It was pretty frustrating trying to learn the API and develop a product quickly.