From 1982: A chance for American kids to sign-up with G.I. JOE.
In the days before the web and social media changed all the rules, Fan Clubs and similar "clubs" were a surefire way of direct marketing to kids. Getting them to sign-up was a great way of harvesting contact details (the Tesco ClubCard of the time) so that direct marketing could then be zapped-out when the toy maker had something new to promote.
ACTION FORCE operated a similar scheme in the UK.
This ad is from the very early days of the G.I. JOE revival.