I'm reading the Treocentral discussion on my Treo 600 a lot (mobile.treocentral.com) and ther's one thing that is really annoying :

When I log in and start to read the "new posts" I can see all the new postings since my last log-in, very nice. But then, when, for instance, I receive a phone call, and after the call I switch back to Blazer and the discussion, I can't use the "back" function, so I can no longer browse the new postings.

It would be nice to have a functionality like "new postings since mmddyyyy"