Hotline clients allow a connection between user and server. They essentially provide the user with an experience, allowing them to view files and folders on the server, read the news BBS, chat and communicate with the community.
Because hotline was originally intended as a chatting p2p client, most people focused on one or the other. Hotline is a good place to find files, however it also houses a fairly large chat community, and allows you to communicate with other users. Since hotline came prior to Facebook, torrents, and the Gnutella network, it truely was remarkable for its time. It still exists, and you can feel free to download one of the clients below and see for yourself.
Stop over to the server: obsession.ath.cx and say hi.
Openline is the source code released under the GNU General Public License.
GLoarbLine (Mac OS X PPC, Windows) adds numerous new features and fixes to Openline
Underline (Mac OS 9, Mac OS X PPC, Windows) primarily adds optional blowfish to encrypt connections with servers that support it
Many hotline users have decided over time to develop their own clones, serving particular purposes that are not available in other clients or featuring a personalized user interface. These are the clients that are being actively developed by the Hotline community:
Obsession, written in Qt, although currently focused mainly on Windows users. As of June 2013, the Obsession client is open sourced.
XCC pr2.5b, test version, please report any bugs. XCC is (for now) a Mac client aimed at end users and server admins. This beta includes full AppleScript support, allowing the client to be used as a customised bot.(Edited download link to Tagban's host to avoid overloading servers of Creator)