It is amazing how little pieces of information that are likely innocuous by themselves can be combined to develop a pretty thorough understanding of relationships.
The sperm donor guy, though... facial recognition? No idea.
This post is obviously sarcasm.
I think that's probably true. You need to spend sufficient time near someone--like within a few feet or so.
I had an interesting experience where Facebook recommended me as a friend to someone I sat next to on an airplane, with whom I had a conversation with. My phone was in airplane mode. Not sure how that happened, TBH!
How did the Sperm Donor know it was his child?
Find that and that's how Facebook knows.
To look at a friend suggestion and know it's your child means you have been in contact with someone past the donation stage.
Nothing about how Facebook offers suggestions are secret to my knowledge.
All that's happening is people are not aware how easy it is to find information from networks
I figure everything down the left aside on FB corresponds to a permissions bit for each entry, so maybe some classes of user get some really fun items over there.
IIRC, connections like those were often explainable by addressbook data. Please assumed Facebook didn't have access to that when it actually did (I'm pretty careful about this kind of stuff and found mine had been slurped at some point, for instance). It's not inconceivable that a psychiatrist and patient may have exchanged emails or phone numbers.