I actually used this video (or a very similar one, same graphics and all that. The video says it was uploaded two months ago but this was at least double that far back) as a springboard for a presentation in a human relations class. I found some willing participants, contacted at random some of their facebook "friends" and interviewed them. Just basic relevant things in their life that anyone considered an acquaintance would know. Then I quizzed the participants on how well they knew them. I don't remember the exact statistics, but something like 20% could answer most of the questions with some accuracy.
As a bonus type thing, I didn't tell the participants the last names of any of the people and asked them to fill in their info included with the random interviewees picture. Only something like 40% could even recall the "friend"s last name. It was a lot of fun to do and I culled my Facebook friends greatly after that.