The current state of play is that an email is sent out when a post is made in a thread that you are watching. The email contains no text information about which thread it is, although it's supposed to contain it in the Subject line and the body text.

Clicking the link in the email and reading the new post works fine. But if you post to the thread the "watch" is automatically turned off, so you won't get any more emails from the thread unless you expicitly turn it back on again.

The latter problem is an old one here - it was a fault before Mike and Co. took over.