New forum design!
We had several goals. The first was simply to streamline the flow, making it faster & easier to navigate and post. The old system required a new page load for each message, which was... well, obnoxious. Each thread still lives on its own page, for some specific reasons, but we've managed to cut down on new page loads dramatically, speeding up the experience quite a bit.
Our other goal was to preserve the advantages and uniqueness of our old system, which is a clear, hierarchical thread structure that makes it easy to see who's replying to what. Other systems that show everything at once, on one page, don't...
I've been thinking about this. I don't have a solution yet, but I'm working on it.
If there's a really interesting thread and you want to know when someone adds something, you can subscribe to that thread. The link to subscribe is in the top-right corner of the thread page.
You can also, of course, choose to be notified by email only when someone replies to your message(s). That's a checkbox option any time you post.