Here is what I got when I typed the URL into my browser:
Thank you for your interest in RewardsPlus. We are currently in the process of reviewing qualification records for the 2014 RewardsPlus program and will resume registrations for the 2014 program on Monday, February 24, 2014.
Though registration for the 2014 RewardsPlus program will be closed for period of time, you can still enjoy the other benefits of RewardsPlus, such as saving 20% when you convert your Marriott Rewards points into MileagePlus miles and the option for MileagePlus Premier members to convert miles into Marriott Rewards points.
Explore Points and Miles benefits here.
Learn more about Marriott Rewards Gold Elite status benefits here.