freenode.net allows topics to be up to 450 characters, but mIRC truncates at 390. Example:
[17:05:34] * Topic is 'Welcome to #FreeBSD || For technical support please help yourself:
www.freebsd.org/handbook and
www.google.org/bsd ||
http://lists.freebsd.org for information on the mailing lists || From 9/7 to 9/13 100% of the money from purchases at FreeBSDMall.com go towards the FreeBSD Foundation || The RELENG_4 (4.x-STABLE) branch is 4.9-PRERELEASE, this is a normal part of the release cycle || We''
/debug shows the full topic:
[17:05:34] <- :brunner.freenode.net 332 Ashkrynt #freebsd :Welcome to #FreeBSD || For technical support please help yourself:
www.freebsd.org/handbook and
www.google.org/bsd ||
http://lists.freebsd.org for information on the mailing lists || From 9/7 to 9/13 100% of the money from purchases at FreeBSDMall.com go towards the FreeBSD Foundation || The RELENG_4 (4.x-STABLE) branch is 4.9-PRERELEASE, this is a normal part of the release cycle || We'll help you to help yourself