How about making two types of account on CSS forum?
One free account and other premium account.

Members will have to pay for premium account which in turn will give them more features on this site.

Lets say that members with free account will be restricted to post in limited numbers in a week or a month but premium account holders can post as much as they want.
Or premium account holders will have the facility to subscribe to posts unlike free account holders.
Or free account will let members to post in or even read selected forums only.

The features restricted to the free account type, can be discussed among moderators and administrator but my point is that to milk the CSS forum completely, users will need to get a premium account.

This way a new member can first get a feel of the forum before paying for the premium account and if he can't afford it, even then he will be able to read few posts.

It will also force the serious aspirants to pay as CSS forum is a academy in itself.