Some say it was 2012-2013 academic year following the significant modernisation and increase in smartphones in the middle of 2012.

There was alot of transitions in 2012. Old stuff like Windows XP get defeated by Windows 7 in popular use that year (i remember my first primary school abandoned this around spring or summer that year), digital grainy cameras got replaced. Smartphones increased. Lonliness, school bullying, anti-social feelings started to become an issue from that year.

But Iphone came out in 2007 and was the first smartphone. Plus, the introduction of iphone had instantly changed the way people used technology from that year.

When people discuss about how the "golden" "non-social media days" existed, they mainly talk about the mid and early 2000s. But barely the late 2000s, which leads me to think that social media became the norm from 2008/2009 academic year. But one comment on a thread said that phones weren't the norm that time.

But I saw one reddit thread and everyone said 2013 and 2012. That is on one generation sub.

While social media took off from the middle of 2012, the general norm of teens and young people being glued to their phones started when iphone came out.