See Also: Decentralized Clients
DirectConnect is a file sharing application for Windows. The network is semi-centralized: Some users run so-called hubs, which are centralized servers that manage user indexing, file indexing, and chat. Once a user is connected to a hub, he will immediately find himself in the hub's chat channel and see a list of the users connected to that hub. He can then browse individual users' files and download interesting ones, or he can search all users on the hub for a specific file.
Hubs can form hub-networks which can be searched collectively; connections to hub-networks are also pooled, so that you are automatically redirected to an open server.
Each hub has its own rules pertaining to user behavior, allowed types of files and, most importantly, the minimum amount of files that must be shared. Users who share no files will find it hard to connect to any hub at all, since most of them require at least some minimum. This enforced minimum has made DirectConnect one of the largest file sharing networks in existence, with many people sharing several hundred gigabytes.
DirectConnect's folder-based file list management is reminiscent of Hotline and Carracho, but it does not have the headaches associated with finding a node that lets you download something. The slot-based queue works rather well, although it could still be easier to find non-busy nodes.
Amazingly, DirectConnect is written in Visual Basic, but it is still quite snappy and very easy to use. It has built-in advertising, but spyware was removed from early versions after protests.
There is also a linux/windows client available DCGUI. Seems to be stable enough for daily use -- C-Keen The client implements a feature not currently found in any other, the ability to "multidownload", i.e. get different parts of a file simultaneously from different people.
ReverseConnect is a newer windows client (it's a fork of DC++) that allows "multidownload" also. Unlike many other clients, hub operators rarely ban people for using this client.