Having had it happen to me, I think I know what CPGenius is talking about.
If you look at the last page of a multi-page thread (say, "What do you do?" for instance), and you post a response to the end of that thread, you are taken to the first page of the thread. CPGenius is suggesting that it would make more sense to return to the page you were just looking at...or the page that was just called into being by the new post.
Personally, I think it would make more sense to dump right back out to the thread list. After all, unless two people are posting to the thread at the same time, it stands to reason that the poster ought to know what the thread says...it would actually make more sense to be dumped back out to the thread list.
--Dave Althoff, Jr.