If the word "IRC" means nothing to you, it's quite likely this application will be completely useless for you.
JSIS collects and shows many different statistics, below is a list of some.
I grew bored of looking at the old stats generated with pisg, and the other generators. I then thought I'd make my own stats program, with a more modern feel to it, and a more modern looking output.
The code in JSIS should also be somewhat easy to manage, and themeing should be pretty easy, if you get sick of the default theme. There's a widget system for adding content areas, e.g. "Most referenced words" in a somewhat simple way.
The code can be downloaded from the GitHub project page. GitHub also hosts the Wiki, and issue tracking. The JSIS homepage at JSIS.name serves as a place to publish documentation etc. in a better format.
Stable and ready are both relative terms. Is it ready? ... probably never will be, as the requirements keep growing as features are finished. Is it stable? If I commit, it doesn't crash for me. There's still a lot more to code, and many features need heavy "fine tuning" to generate better statistics.
Is it usable? It should be, assuming it happens to support the log format you need.
Some features that aren't ready:
At the moment, JSIS supports the default log formats of:
Some clients etc. are pretty dumb and alter the log format based on themes etc., you might find help with cleaning them up to a format that can be parsed in the Wiki.
If you've stuck here for this long, you might be interested of the licensing of this awesome creation. Worry not, my friends, this thing is open source.
JSIS itself is released under two licenses: new BSD, and MIT. You may pick the license that best suits your development needs. The exact text of both licenses are provided with the source code.
Please refer to the documentation.