I've had this on my mind for a long time, but haven't bothered to post it yet.
At the moment, the subject of the notification email says "Dropzone.com Forums - Reply to your post". Once you see that you have, say, nine messages with that same subject, you have to open them all to see what thread the replies were in and who replied.
How about changing the subject to for example : "Dropzone.com Forums - Reply to [insert your thread title here]". Or even "DZcom Forums - Reply to [thread] at [a forum]"
That way it would be unnecessary to even open the notification messages, which can take a while with a slow modem connection.