I am looking for such a feature too!
There are many threads i want to know if something new is posted.
Best is, if they apear in "my Forums".
There is the "notify" button on top of threads, but you only get an email
if someting new is posted.
I don't want to get dozens of mails every day, where i have to click.
It's better, if the theads or ordered in "my forums".
Most other board have a button "subscribe to thread".
I am sure there must be such funtion in the software or an add-on.
When the search is not working right, it's even more important.