Prosody is a server for Jabber/XMPP written in Lua. It aims to be
easy to use and light on resources. For developers, it aims to give a 
flexible system on which to rapidly develop added functionality or 
rapidly prototype new protocols.

Before you can run prosody you'll need to look in README.SBo.

You need a "prosody" user and group prior to building prosody.
Something like this will suffice for most systems:
  groupadd -g 274 prosody
  useradd -u 274 -g 274 -s /sbin/nologin -d /var/lib/prosody prosody
Feel free to use a different uid and gid if desired, but 274 is
recommended to avoid conflicts with other stuff from SlackBuilds.org.