All other forums that I belong to send me an email that links directly to the newest post that I have not yet read, not just the (current) last page of the thread (it has www.domain/sitename/threadtitle/post#). If I read the last post of page 3, I will get an email when there is another post. Unless/until I visit the forum, I will not receive another email update for any additional posts.
When I click the link in the email, it takes me to the first new post that I have personally not read yet (this is very easily done with a tracking cookie and pulls up that post number in the thread). If it has been a few days and several posts have been added since I visited and the thread is now 5 pages long, clicking the link in the email still takes me right to the first un-read new post back on page 3. I don't have to guess where I left off, how many pages there were/are, or which post on the page I read before any more were added.
A HUGE improvement and convenience in my opinion, and it also limits the email clutter in my inbox by not getting an email for EVERY new post (just one email unless/until I visit the thread again).
It is most certainly possible and is the way all other forums I belong to function (as far as I recall). Consider it a useful site/feature request...