I registered back in 2007 when they were Corporate Research International, so It's been a long time, but I think they accepted everyone that applied. There may have been a wait while they verified the SSN to make sure it was legit, but I'm not certain about that. I can't think of any other reason they wouldn't tell you the status of your application in a timely manner.
They have 3 or so websites. I am registered with all but each has a different url, username, password. I don't know why and it is very confusing. Seems like one site handles MS, another recalls and another does audits.
I applied and was accepted by them pretty quickly. But it took about 3 weeks to get my SS approved so I can sign up for shops (only one gas station chain) but it helps a bit on my gas bill every month.