IRC is full of noise. It's nice to have your hilights in their own window. This module does that.
Why is a module, I hear you ask, rather than a Perl script? Because Perl is an abomination unto God. Irssi's script mechanism doubly so. So if you want to go to heaven, you had better use this module instead. And remove Perl support!
You will need: some hundreds of irssi header files, a C compiler and linker,
and make. First download the source of irssi-hilightwin, then compile the code
using a simple make. If you don't have the Irssi source code, there is a
downloader provided. Just run it. Since it might download the wrong version of
Irssi, you're probably better off just reinstalling Irssi and keeping the
sources somewhere.
Irssi looks for modules in ~/.irssi/modules/, so I suggest simply moving
libhilightwin.so there. Then load it into Irssi with /load hilightwin.
Actually, just add the line load hilightwin to ~/.irssi/startup. Boom.
Then there is the windows. Create a window named hilight by the following incantation in Irssi:
/window new split
/window name hilight
/window stick on
/window immortal on
/window shrink (... shrink until satisfied)
/layout save
That's it, really.