www.intervalworld.com
That is the web address. It seems like you are saying you already belong....
Most members of II and RCI don't use them for any travel plans....and do use them in order to trade their weeks for another place.
Aside from the independents, there is no other way you can trade your Marriott week.
www.ownertrades.com might be helpful
However, sometimes, the exchange companies have super value weeks (getaways or extravacations) that no other travel site can compare....
And of course, if you have a very good lockout week at a Marriott resort, if II wants your week bad enough, they can give you an AC (low priced week with restrictions)
So....with the lockout of one week for two weeks, and the possible AC for a third week....maybe you should stay at TUG, and read many more of the tricks that we use to try to push the value of the timeshare to its full value potential.....including using II (or RCI) (Or the independents) to their full value.
Learn a bit more about usage with & without an exchange company. Then see if you think the membership is a value to you.