If you still want to take part in discussions on the official Crowfall forums, you’ll have to back the game. The game has locked down its forums for all non-backers, giving new registrations access to a limited forum for 30 days for potential players who want a glance at the community. Other than that, if you want to talk, you have to pay.
All forums will remain readable for everyone, whether you’re a backer or not. The move is supposedly to lock down less than constructive comments from non-backers that have the potential to derail useful conversations. If you aren’t currently a backer but still want to remain active on the forums, you can either jump in at the $5 level or just wait until the game starts moving into its non-backer testing phases.