The subscription notification engine has been updated so it now sends only one e-mail until you view the topic--no matter how many posts are made in the meantime. I tested it out and it seems to work fine, but please report any issues.

Due to the way the new engine works, you might not get an e-mail for the next update for any topics you're subscribed to. It should work fine once you view the topic though and for any new subscriptions moving forward.