What is 420 on a dating site?

User of Cannabis or Tolerant of Cannabis Use is the most common definition for 420 FRIENDLY on adult dating sites, as well as on Snapchat, WhatsApp, Facebook, Twitter, and Instagram.

Whats the story behind 420?

Origins. In 1971, five high school students in San Rafael, California, used the term 4:20 in connection with a plan to search for an abandoned cannabis crop, based on a treasure map made by the grower. The Waldos referred to this plan with the phrase 4:20 Louis.