Hey there, it's open to be browsed by everyone except the user uploads and requests forums...the reason being the protection of our users.
You don't have to login each time you come to the forum either, just check yes on the option "Remember me? If enabled, you will be automatically logged in again when you visit."
Argh! There is a problem with the site redirector causing members to not be able to login automatically for some reason. Hopefully this will be resolved shortly. Sorry for the incovenience.
EDIT: This was fixed by the way, forgot to mention it earlier.