After much pressure from relatives, and with great reluctance I joined F/book at the weekend. I cannot possibly use my real name as it is so singular, but my chosen nom de plume identified me to my own relatives. They never had my real name, real date of birth, real location or any other identifer which is user-supplied.

I carefully checked all the security settings and deleted cookies every time I exited.

Today I went back in there on a different computer for a final search for a sisterinlaw who had been nagging me to join. Yet again I failed to find her. While I was hunting around, F/book suggested that I use another search tool, which I clicked upon.

To my horror, another window opened and it said "You also have this yahoo account. Give us permission to look in there for your friends."

F/book had NEVER been told of that Yahoo account of mine. It was obviously NOT the one I had used to register. Furthermore, it is not a Yahoo account which any of my relatives use: it is a back-up work account and rarely used.

If that isn't the creepiest computer experience I've ever had, I can't think of one which beats it. My F/book account has now been deleted. Somehow I doubt that that will stop them spying on me/my computer/s but I've done my best.