They should do things like they do on ichumon with the game forums. People should visit the first page to familiarize themselves with the rules, but they are not allowed to post unless they are on the last page, so they can keep updated with the game.
For example (playing, I dunno, the wishing game?):
Player 1: I wish I had 54 doughnuts!
Player 2 (who was reading the first post, but didn't go to the last page to see the last player): But the t-rex ate you!
Not allowing people to post whilst they are on the first page would prevent the above.
However, on threads such as commission thread, this is not necessary. This preventing of posting on the 1st page could be optional. It gets annoying when you have to go to the last page to post when it is not necessary.