I'm a former professional librarian. Left the field in 1985, but have never heard of anyone anywhere paying for use of the dewey decimal system. OCLC services is a different issue. You're paying for their provision of cataloging for your collection.
I was completely unable to get it to "scroll": iPhone, MacBook running Firefox or Chromium, trackpad, arrow keys, the handle thingy on the right edge of the browser... nix nada nothing.