"Although by default XChat doesn't offer all the user-friendly options in its configuration dialogue, its true power stands in the possibility to configure it using /SET variables and Perl/Python scripts or even C plugins. You can practically make XChat behave in any way you want: from a powerful, personalised IRC client for daily use to an IRC help or trivia bot...
"The conference mode can be turned on/off using the irc_conf_mode variable (which by default is 0 - disabled). By turning it on, the join/part and quit messages will not be displayed anymore, so you will be able to keep a log from an IRC meeting/tutorial/discussion without those annoying messages. Use it like this:
"/SET irc_conf_mode 1
"If you still want to see the messages on other channels, right-click on the channel button, go to Settings -> Hide Join/Part Messages. Tick (or un-tick, depending if you want to see them) this option."