[Arryn]

The "disorientation" never fades. In English, you read text from top to bottom. So you scroll down to where the Last post you read is, read that post from the top down, then scroll up to the next post, read that one top-down, scroll up again, repeated over and over. It's simply unnatural. The idea of having the most recent post on top is only useful if a thread has so little activity that there's a good chance that the post at the top is the next one for you to read (ie: follows the Last one you read). In practice this is hardly ever true.

Another "bright idea" by an engineer (programmers are engineers) completely out of touch with real-world Users.