You wouldn't know Bitcointalk is big place until you become one of it member
it's not all about that but being a active one
newbies cannot message other members, they are restricted by default but ranks above can make use of this feature and communicates effectively.
Am not sure if buying corper membership rank could help evade this
Really? Newbies can not message another user? I was not aware of this restriction of newbies. OP how did you know that newbies can not do that? That means, in your newbies days you were trying to message users and you could not or the OP account is an alternative account of a legendary member.
Yes I believe if a newbie buy a corner member, the newbie can free from the restriction.
Yes. From the OP, one can not do anything in the forum until you are a registered user if not you will just be a guest which you can only read but can not do other wise. And also yes. There are a lot of benefits in the forum. You can even bring your services to the Forum for advertisement.