Yeah, email was the social media before social media especially in the 90’s and early 2000’s. I got into Linux in 2005 and that’s also around the time Digg and Reddit started growing. I was never into social media like Myspace and Facebook but I spent a ton of my high school days on Digg.
That said I realize most millenials didn’t get into FOSS or Linux but we did use computers a ton regardless, and smartphones were available by high school/college for most of us.