When I left school in 1982 to up to Oxford, I wrote myself a note and put in inside a book that I was sure not to lose. That note was a list of names of people that I should not forget. So I had a look to see what had happened over 27 years, 4 house moves and over 20 long foreign trips:

Scouts

Neil Dallen - was still a GSL at 7th Epsom, so connected through Scouting
Norman Dallen - RIP
Robert Allen (Venture Leader), and his wife, Alison - lost touch
Mark, Lindsey, Spencer Blackford - lost touch (though bumped into Mark in the City 10 years ago)
Tim Hallet - lost touch
Paul Baker  - lost touch
Brian Jackson - still connected on Friends Reunited
Karen Bramley and Mark, her husband - connected on Friends Reunited
Gary Bowyer - connected through my brother still
Mike and Judith Lovett - lost touch
Tony and Francis Miles - in touch (Tony is in Christian Media and an avid social media user)
Peter Townsend (Simon and Jane) - lost touch?
Peter mcNeil - on Facebook
Dave Mitchell - lost touch
Kevin Reynolds (who blew himself out of a tree) - lost touch
Stephen Matthews - lost touch

Other Friends

Ian and Mike Thoburn - lost touch
Sarah Kenyon - lost touch
Hillary Gunson - in touch via Friends Reunited
Mark and Jane Norris - keep trying to meet for a beer and failing! Have email address
Rob Norris - lost touch
Alison and Charles Hill - lost touch a few years back, but could find an address for parents
Robert Hill - lost touch
Tim - lost touch (also, despite him being a daily friend, I have no idea of his surname!)
Jacqui Saviel - married Graham  - - lost touch
Rick and Karen Player - still in touch regularly

Without email and social media I really would not have had a hope of finding any of them again. Social media does have a utility, but it is far, far from perfect or universal right now.