Hmm, never tested it out, so you might be right about it remembering. You're the second one to comment on it. It doesn't really bother me since I like to use the icon to the left of each forum. Grey = no new posts and blue = new posts. Also, I tend to look at the homepage. It tells you the last 10 posts made on the forums. I use that the most to see what's been updated since the last time I checked the board.

Reputation works like this. For every post made there is an icon that users can click to leave feedback for that particular post. So, if you really like what someone posted (found it funny, informative, etc.) you can leave feedback for it. The more positive feedback you get on your posts, the higher it goes and vise versa. It's a way to quickly see which users contribute usefull posts and what not.