to answer your question, I went to the source: the software which permies.com is based on (called simplemachines)
and found this page in the online manual which explains how we can tweak the URL parameters to get RSS feeds for individual "boards". In simplemachine terminology, a forum is composed of boards which are composed of posts
it also shows how to change the limit from 5 to whatever
FYI - setting up another link to your feedburner email version allows those who do not use or know about feed readers to simply subscribe to the feed and receive email updates once every day. So instead of individual emails it's more like a daily digest, which works better for some.
Your feeds included any changes to pages, not just posts, and you can edit your feed pages directly to send out messages not posted on the website proper. Lots of cool stuff to play with.