What happened was: I'd mentioned in a comment some of the fun things that my father's done over the years, and knowing that he'd had various articles with photographs published in Strictly I.C. (a magazine for enthusiasts of miniature internal combustion engines) I wondered if the SIC site had any of Dad's photos. It turns out that Robert Washburn, the editor, hadn't actually made much of the site, alas, so I thought that trusty old Google might pull something up of Dad's.
The problem is that while 'Dekker' isn't a common name in England, it's very common indeed in the Netherlands, so searching for my father's first forename plus surname found lots of people, nearly all of whom aren't Dad :) So, clutching at straws, I Googled for Dad's full name, not expecting anything much...
One entry. In Dutch, perhaps not surprisingly, and when I clicked on the link it 404ed on me. Hoping against hope, I tried the cache.
Not only Dad, but his brothers and sisters, his parents, his Dad's parents... My Dutch is rusty at best and mostly limited to breakfast conversation, if that, but it didn't take me too long to work out that at some point my cousin Pieter (five years older than I, and my uncle Harry's son) had been doing quite a lot of genealogical research. That document led via the Wayback Machine to a couple more genealogical sites and documents...
To cut a long story short, as far as I can translate I'm descended from Jacob Dekker who was baptised in Zijpe somewhere around 1697, and then there's stuff that I can't translate which connects me to Jacobus Petrie who got married in Wervershoof in 1640. I also seem to have a great-aunt of sorts called 'Rosalia Seraphina', the poor dear.
I've printed it all off and sent it to Dad (I still haven't persuaded him that he'd have enormous fun with a computer and a net connection) for his interest.