Someone's just emailed to ask for advice about managing the deluge of emails Moodle will send you if you don't keep an eye on it, so I thought I'd repeat my response here for anyone else who might find it useful.
- when you make a post, there's a setting which automatically subscribes you to that thread, so it will email you everything. You can look for that setting when posting, and make sure to turn it off
- from the 'all discussion boards' page, you can tweak your subscribe settings to make sure you're only subscribed to the threads you're interested in
- when you edit your profile you can set Moodle to send you daily digests instead of one message for each post
Hopefully some combination of these will help you set things up to suit you. And do feel free to post here with any useful tips you've discovered that other people might be interested in.