The LA Clippers required a sign-up form to allow fans to opt-in to their mobile club.
http://www.nba.com/clippers/text
LA Clippers
The LA Clippers required a sign-up form to allow fans to opt-in to their mobile club. They would then receive updates from time to time about the four options below. 1) Scores and news 2) Ticket offers 3) Events and player appearances 4) Clipper gear offers. http://www.nba.com/clippers/text