for a start, just to let you know where I'm coming from, and that our users are somewhat close to insane:
our biggest thread has 1265 replies and 14943 views.
this thing is loading *forever*, I have no clue whatsoever, how they keep track of replies to single postings.
our busiest user has something over 20.000 postings, I have roughly 15.000 - and as an "official represantative blablading" of our site, I need to know if someone replies to me in one of our numerous forums, without subscribing to the entire thread, which would KILL my mailbox.
so we really really *need* more in depth subscription options.
Either a config setting in "my home" like
"email me replies to posts I made"
and / or
the ability not only to subscribe to entire threads / topics, but to subscribe to single postings or even branches of a thread.
I admit the "branches" feature could confuse some people, but introducing "favorite postings" in addition to "favorite threads" makes sense.
And if even that still seems to be too complicated for the average non-power-user, the aforementioned config option would be easy to understand, and a killer feature for us as well.
plz include this in 6.5, or, if there is a mod for this that I have overseen - slap me silly.

I strongly believe this feature would increase quality and quantity of communication drastically (hello page impressions), especially regarding power users!