Jabber is a set protocols for messaging between two clients on the Internet. It's main use is as a Instant Messaging protocol. The messaging protocol is open/free and a proposed IETF standard (called XMPP). The protocol uses XML as the data format.
The Jabber protocol provides the following features:
- Basic Instant Messaging (IM) functionality
- Group chats
- Messages and chats
- Messages to offline users
- File transfers
- Interfaces to legacy and common IM protocols: ICQ, AIM, Yahoo, MSN, ...
- Multiple servers, which may or may not be connected. This makes private servers possible.
- Pure Open Source XML based prototype.
- Jabberd -- the open source server developed by the jabber project.
- Cabber -- Console based
- centericq -- Multi protocol, including jabber
- Gabber -- GTK based
- Gaim -- Multi-protocol, includes jabber
- Kopete -- Multi-protocol, includes jabber
- MCabber -- Jabber console client (using Ncurses)