Is there any way to force users to make some posts before they can view a specific forum? Does it exist already?

Never mind, I found this plugin.. can there be any way so that posts are required to make threads?

Go into your forum permissions and deny the ability to "Post Threads", but allow the ability to post replies. Then create a new group with the ability to do both.
For example
Group 1 can post replies in General Forum, but cannot create threads
Once their post count reaches 10, they are promoted to Group2...which has the ability to do both in that particular forum.

There's this plugin, though you have to have that number of posts before you can even view the threads in the forum: http://mybbsource.com/view/50/

Oh, I feel stupid now, ¬_¬

Thanks a lot. I created Second Group Promotions, and it works.