I remember a viral twitter photo of Sophie Turner smoking a Juul while filming the last episodes of Game of Thrones

Juul changed the cultural standing of vaping and (for a very brief moment of time) made it "cool" by means of social media celebrity promotion. They were hit with pretty aggressive punishment for this by the US FDA if I'm not mistaken.

Juul was founded in May 22, 2015 well after Vaping was in a fairly flat growth trajectory, and afterwards there wasn’t any kind of noticeable bump in adoption from such efforts.

https://en.wikipedia.org/wiki/Electronic_cigarette#/media/Fi...

All the exponential curve stuff happened early on the path from 0 to ~10 of million.