Birth date and I guess town also, so two things both very publicly accessible through the registry of deeds or whatever. I found mine rather quickly as well as a couple friends/relatives, haven't bothered to look up any strangers. And you don't necessarily start with a random row, can search whatever info you have on someone and see if anything pops up.What's that, and how does it get tied back to an individual record on those spreadsheets? I mean, it can certainly be done, but I think any of us would be hard pressed to look at a random row on there and tie it back to a specific individual.
Then there's the personal transfer exchange of info that gives you everything to really nail it down...