UNLESS WE PROVIDE YOU WITH SPECIFIC NOTICE, NO CHANGES TO OUR TERMS OF USE WILL APPLY RETROACTIVELY. You may be able to access and view some materials for free and without registering for an account, but certain features may only be available if you (a) register for an account and sign in to the associated service. or (b) if you subscribe to the service and pay the associated subscription fee. </p> <p> </p> <p>YOU MUST BE EIGHTEEN YEARS OF AGE OR OLDER TO REGISTER AND USE THE APP. YOU MUST BE EIGHTEEN YEARS OF AGE OR OLDER TO CONTRIBUTE USER SUBMISSIONS TO THE APP.