This is the plain vanilla feed. It only contains posts to the weblog made by me. Good if you don't have a lot of time to read stuff.
The basic discussion feed is a little more exciting, offering the start of all threads in all the dicussion forums. This represents a reasonable amount of traffic.
Weblog & Discussion
This feed combines the weblog and the discussion feed. The best way to keep up to date with most of what's happening at iamcal.
Weblog & Discussion, with replies
The feed to end all feeds, this contains all messages posted to iamcal, and thus can be quite busy. In any day there can be upwards of a few hundred posts. Beware, hardcore iamcal addicts only.
If we don't have what you're looking for, perhaps a customised feed would be more suitable.