Have you tried looking in the subscriptions part of your profile? if there is an option to easily unsub en mass, it'd likely be there.

Personally I never use subscriptions myself for precisely the reason  of too much mail, I always find the new posts links more than adequate.

Slightly off topic but closely related, I'd like to see the forum runner plugin installed on this forum; it would make those of us who have IOS devices and who wish to keep up with the forum while we're elsewhere that is not at home and sitting at the computer a bit easier.

An interesting question; I honestly don't know.  I decided to give this app a shot less than a day ago and came across this topic at the same time, which is why I thought of the plugin.

Hmmm, my results seem to indicate no PunBB plugin currently exists, though I suppose it wouldn't hurt to suggest the idea and explain why.  Their team seems well dedicated to its users from everything I've read thus far.  A quick email regarding voiceover support resulted in a reply within about 5 hours with reassurance that voiceover was indeed working well with the app.  For the time being, all I can do is hope. 

By the way, should anyone care to find out more about the app they can do so by visiting the following address:

http://www.forumrunner.net/

This is just an observation, but it would appear that PunBB isn't too popular with the plebs, and the software is updated fairly infrequently. Personally I say that's a vote of confidence, and thanks to this forum I now know there exist forums that don't require heaps of javascript stuffed with crap features nobody will ever use which load really fast, but it does mean integration like this is probably going to be harder to acquire. The flip side to this is that, sad though it is when only a touch-screen smartphone makes the need evident, people are increasingly aware of the need for native apps for this sort of problem.