Development of the comment system was really painful; it only took one evening but the way it's plugged into the server made it quite irritating to debug. It's written as a handler under Medusa (the web server layer), which makes it run very quickly, but debugging is problematic. Sometimes the system seemed to just completely 'lose' Python exceptions, and I had to restart the server every time I changed anything.
If you're used to working under mod_perl or in ASP, this sort of thing seems very very slow. So right now I'm getting a general caching script handler going, which should make my code/test cycles somewhat quicker and also fix the exception problem (by properly catching everything in the right place).
Once this goes, I can do some of the more interesting bits like referrer tracking and log analysis (these are what give you the rcsPublic/ pages that tell you who's connected to who).