One thing I think Mudcat does extremely well is signal whether there is new mail since you read a thread, by including the number of posts in the URL (this is hidden; but if you've read the last post it shows up in your "been there" color (usually magenta) and if there are new posts since you've read the thread, it shows up in your "never been there" color (usually blue)).

I've never seen another conversation system on the 'web that does this; it works really nicely.

One feature that I wish Mudcat had, is making multiple pages of a thread that goes over a certain number of posts. (Example at blicky). This way when things get too long it doesn't take "too long" to load.

Alex