The link in Wiki up top still seems valid, it does take you to a page that state 50K sign-up bonus. But I was curous that if you login to your Marriott account, what offer do you see, the 50K link or the 30K Link.
alc, based on our experience with different Marriott Rewards accounts (big family!) you'll see the 50K offer if you are Silver status (or higher). Else only the 30K offer.