Simple IRSSI plugin used to add a timestamped line to the currently focused window (bind it to control-space to easily keep track of how far you have read).

mark.pl

#!/usr/bin/perl
use strict;
use warnings;
use Irssi;

our $VERSION = 0.1;
our %IRSSI = (
    authors     => 'Brendan Johan Lee',
    contact     => 'deadcyclo@vanntett.net',
    name        => 'mark',
    description => 'Adds a timestamped marker line to the chat buffer. Bind it to control-space with /BIND ^@ /mark',
    lisence     => 'Use it for whatever you want, but at your own risk.',
);

sub addmarker {
    my $awin = Irssi::active_win();
    my ($sec, $min, $hour) = localtime();

    $awin->print("%B█%0%B%8$awin->{'name'}%8█  $hour:$min:$sec  %8%8█████████████████████████████████%N%B%N",MSGLEVEL_CLIENTCRAP);
}

Irssi::command_bind('mark','addmarker');

Works best with a powerline enabled font