NeoGAF membership is not automatic or guaranteed. After creating your account and verifying your email address, your account will be approved or rejected manually by the NeoGAF staff. This process takes time, and we have many thousands of applications to process, so be patient.
If you attempted to register and were unable to due to a banned email address, keep in mind that only ISP, workplace, and educational email addresses are permitted for NeoGAF accounts, to ensure a higher level of personal responsibility while keeping NeoGAF membership free. Note that a small number of ISP email providers are on the ban list as well due to potential for abuse.
If you are rejected after successfully registering and verifying your email, your information was deemed invalid, usually based on email address (but sometimes for other reasons, such as an inappropriate username or an attempt at ban evasion).
If you are approved after successfully registering and verifying your email, you will begin as a Junior Member. This is a probationary period where you will be unable to start new threads and there are harsher penalties for breaking the ToS. Follow the rules, be civil, and try to contribute meaningfully to discussion and you will eventually be automatically upgraded to Member status.