Topic Notification E-mail

boRg,

This cropped up in the suggestions list in a slightly different form but I wondered if there was a workaround yet?

If a user turns on E-mail notifications for a topic, then he/she gets a separate E-mail for every reply.  On a busy board that's almost the equivalent of being deluged with spam, so would it be possible to just send one notification E-mail until that user visits the topic, then when they do so the notification count is reset... they get one more message for new replies... and so on.