One of the guys at work wanted to get a notification when just one branch of his repository received a commit. I tried setting it up in the master.conf but never could get it to work for just one branch. Finally I googled around and found a nice explanation of how to do it with loginfo at this website. The one minor issue I had was that the mail command on my cvs box did not include a -s flag, but I changed that over to mailx and we were up and running.
It goes without saying that you don’t want some propietary commit info to be sent in notification emails so if a developer requests this sort of set up ask a few questions about what data will be needed. Also, add yourself to the notification list for a little while to see how the developers are using the tool.
Also, this is usually a beginner level issue, be sure that your box is configured to relay mail out. A simple test message like below should get you an email in your inbox(check junk and spam filters).
Enter this as one line:
echo "test body" | mailx -s "test subject" email@example.com,firstname.lastname@example.org