If you were previously an active member in the forum, you will likely find that there are new rules and a revised structure to the forums. This is a move that will likely prevent some new members from sharing thoughts with others, although it had to be done as people were "bashing" one another and sharing negative thoughts on Entrecard.
I don't think that the changes will make any huge difference, as the average user that posts in the forum already is a) an Entrecard member and b) has purchased at least 400 ads.
The only people that this targets are those that want to introduce others to their blog and want to get some insight into the system before joining. They will only be able to access the support areas and none of the other areas.
Details concerning this change can be found here.