I wonder why no-one has done that yet: a client for multiple file sharing networks. What we have now is very technology-driven approach: finding files on a particular network. While it makes sense from the implementation/programmer view to have a separate client for each file-sharing network, it doesn't serve user's goal which is to find files. What do they care where the file is? It might be that we're just in the first stage of file sharing software evolution. We've seen that with IM software. First we had a client for each protocol but then someone must have had a revelation: those protocols are fundamentally about the same thing and not that different. Thus a first multi-protocol IM client has been born. The same will happen sooner or later for file sharing networks.