On the top of this page (or any other) is a line of links - one of which is "upgrade!". If you upgrade, you will be able to do the things that you can't at the moment - cost of $12 (subscription), $39 (sponsor) or $105 (lifetime member) - can't ever remember the prices, but that's roughly what they are.
Non-subscribers cannot edit their posts, nor their profiles and what else I can't remember - private messages is another.
The reason for this new method, is to get people to subscribe & help pay the costs of these forums.