Neither myself nor OH have any online presence at all. Nothing anywhere to identify us, no photos, nothing, zilch, nada. He has a facebook account with a fake user name so that he can join local facebook groups and his special interest/hobby groups, but doesn't post anything - he's definitely "read only". The nearest we have is our names are on the Companies House register as we're directors of our limited company (but not our home address), but otherwise, nothing, not on the public voting register either and not in directory enquiries. We don't even have our names on our business website - it's completely anonymous except via the Co House directory. Anyone wanting to find us (i.e. long lost friends/relatives etc) would really struggle.
We've managed to persuade our DS to have minimal SM/internet presence too. He does all the usual twitter, facebook, instagram, whatsapp etc etc but has his privacy settings as high as they can go and limits his SM to specific friends and groups, etc., so again, I think anyone outside of his friend circle would struggle to find him - we've looked at his twitter and facebook accounts and access is very limited and there was nothing showing publicly other than basic generic stuff. When he was at Uni, the careers office advised him to set up a linkedin account which they thought would help with job hunting, so he's done that, and now he's got a job, his employers (blue chip firm) asked him to update his linkedin with his new job, job title, employer, etc., which he's done, but it's all very professional and there is quite a lot in the employee handbook about not bringing himself/employer into disrepute with SM posts which apparently is a disciplinary offence! His Uni careers advisor was adamant he should be very careful with what he posted on SM because potential employers would search him out and anything "out of the ordinary" could scupper his chances, i.e. extreme politics, anything other than "normal/average" partying photos, etc. (some of his job applications required him to enter his SM user names for each platform etc so they could check him out!).
Me and OH have nothing to hide, we're just very private people and hate any kind of attention. We also "compartmentalise" our lives, so my work colleagues don't know my hobbies/interests nor my family - "never the twain shall meet" is our motto!
I think having zero/minimal online presence is a lot more common than people think. Over the years, I've certainly tried to track down a few old school friends and a couple of old boyfriends (just for nosiness/interest really) and found no trace at all. I know OH has also tried to find some of his old friends and old work colleagues and not got anywhere either. We're hardly ancient, both in our 50s, and both been into computers/progamming/gaming etc since the 80s and some of our long lost friends/colleagues were also well into IT and computers, but, like us, they clearly aren't into being "out there" on SM.