Actually I think the biggest activity drop is when the post notifier is down, since all the IRC people forget to check new posts often. Of course Omnom being down doesn't help much either, though.
Since my hardcore moding of the source code it never crashed yet (hardcore modding as in you can only quit the bot by killing the task, even if it throughs errors it still continues.....) so i hope that isn't a problem anymore.....only OmnomIRC....
