After a decade of batchelor-hood in my 20's I joined a dating agency and through them met my wife (circa 2000). The agency actually broke their normal rules of matching people locally and paired us up even though we lived 120 miles apart.
I was working (and always had - from 1991) in Ipswich, having grown up in a small village in the highlands of scotland. She spent early childhood in Glasgow but was soon moved to Corby (Northhamptonshire) where she grew up and still was (from about 1974 onwards).
The dating agency (old style paper-based) matched us up and, to cut a long story short, we got engaged. This of course triggered more interest from the rest of the family. What we actually discovered was that my wife's uncle, still in Glasgow, knew of me, working 600 miles away, and of my family in the Highlands. i.e. he could pin-point who I was in his knowledge of friends and acquaintances. (I on the other hand, didn't even know he, or my wife's family, existed).
Here's the chain of connection.
Her uncle, "G" always worked for BT as an engineer in Glasgow (70's onward?). I also worked for BT in R&D since 1991.