This may explain why someone was suggested to me on Facebook who has no mutual friends. It was someone I once met and who had my email address. I don't let any site read my address book. I have few enough friends that I can find them manually.

I think when you let Facebook consume your contact list, all bets are off on what they'll do with it, though some people will gladly do it in the interest of making things easy (I think it's crazy to both share the account credentials and provide that much data). It's an unfortunate side effect that the contacts in that person's list now have relationship information about them known by Facebook that they may have wanted private or undisclosed.

The right thing to do for Facebook would be to remove data that was skipped, but then they do miss the opportunity for the other person (in this case, you) to recognize and friend the person that skipped you for whatever reason.

It's all reminiscent of Facebook Beacon, which after the whole fiasco added the option to "turn it off" though it really says it won't display that data. It doesn't say it's no longer collecting it. After all, the more info they have the more money they can potentially make by customizing ads, getting more people on facebook, etc.

This is really very dirty behaviour of Facebook isn't it?

Privacy is so yesterday

thanks for the info. i was wondering why i was getting suggestions of people that are in my gmail contacts even though i have NEVER uploaded my contacts to facebook or given them access to my gmail account.

i thought they were somehow (wrongfully) getting access to my gmail account.

Turns out it's all those other people that have me in their contacts!

hmmm now i know who 'skipped' me when going through their contacts!!

Facebook would never pass on the chance to use your data. It's $$$ to them. They milk it with a vengeance. The "viral" model for expanding user base works much better that way...and user base = valuation. Simple as that. They have many more tricks up their sleeves.

LinkedIn is doing this from their start... Although you can control this "Address book" later on and delete all "unused" contacts.

I can confirm similar behavior with my Facebook account. I was recently suggested a cousin of mine who had no friends at all-- yet his address was in my Gmail contacts which I had recently imported into Facebook.

It's very possible that they don't keep your contact emails on file but rather a one-way cryptographic hash of them--that way they could match up friends without keeping your email addresses on their servers.

So, Philipp, have you succumbed to the dark s... I mean to Facebook?

Beau, I guess that's possible too, but I think it's wrong that they're storing and displaying the relationship at all, given that you kind of already confirmed that this person isn't your friend.

milivella, Philipp didn't write this post, I did. Hence my details are being shown in the screenshots and my name is at the top of the article... ;-)

Ditto on this... I had this experience just yesterday... distant relative, no mutual friends, no idea how Facebook knew we were related. But I didn't look it up as I had an exam to revise for! This makes sense though.

this is part of the deal that was required for the venture capital from the CIA :-)

Jeff Atwood blogged about "import" functions like this about a year ago. In my opinion, his arguments are still very valid: http://www.codinghorror.com/blog/archives/001128.html

True. On email. If B in A contacts => suggest A to B.

Tony: sorry, I came here from Philipp's (friend)feed and I was guilty of speedreading the whole thing (thinking that you was the post author's friend!?). Shame on me.

Tony: "I think it's wrong that they're storing and displaying the relationship at all, given that you kind of already confirmed that this person isn't your friend"

But the other person has not confirmed that you aren't their friend. I think they should be provided/suggested the chance to request your friendship (even if you subsequently deny it), given there's obviously some sort of relationship (unless, as you point out, they're spamming). I'm less concerned about this. I think friend suggestions should be as comprehensive as possible. You can ignore them...

And if this feature is abused in the way you suggest might be possible, surely the quality of suggestions will go down, at which point Facebook will surely respond.

Not sure what the fuss is about.

Roy, the reason I'm concerned about this is that who have I have in my email contacts is my own business. Perhaps I have some business associates in there, or ex-girlfriends, or people that I've had email communication with because they've been e.g. using my website content without my permission. None of those people are my friends and I would never want them to connect with my on Facebook.

Not only does a contact not always mean a friend, but they might not even know my true identity, since an email address can be pretty much anonymous.

But this behaviour would mean they not only get to find out my real name, but they could also get to see my profile (depending on my privacy settings), they could see who my friends are and try to add them (again, depending on my privacy settings), etc.

Tony. I agree. They have no right to access our email contact for any reason without our permission. We should be allowed to add or skip whomever we fell like adding or skipping. That is an invasion of privacy. This post answers some quesions. But I was having people suggested to me who DID NOT have my email address and who didnt even know my real name. And one had facebook long before I did and was never suggested to me till last week. That tells me that facebook is doing more than just saving skippd email contact lists.

"... the reason I'm concerned about this is that who have I have in my email contacts is my own business."

You made it Facebook's business as well by giving them your email contacts. Your 'not-a-friend' could just as easily have found you via search .. unless, as you stated, you prefer to keep your profile private and unsearchable. This is a yawner.

Maybe they did add you as a friend but somewhere along the line you never received an email and you ignored the friend request or accidentally ignored it?

Just summarizing this, as some comments seem to speak against each other:
   User A has mail contact with user B
   User C is a friend on facebook of B
   User B searches for friends using his mail contact list
   User B doesn't add user A
   User C gets user A suggested

But in that case @Tony's last comment was totally offtopic..., as anybody can find your facebook name if they know your mail, as they can simply search for your email address on facebook...

Aside from that, the first scenario I mentioned is pretty neat, only problem is that facebook is keeping it a secret...

Imagine my consternation when I had a friend suggestion upon signing into Facebook with the same name as my recently deceased grand-dad. It is this type of thing Facebook must consider when invading your private contacts.

I observed the same thing. Apparently some long-lost contacts allowed fb to scrape their contacts list.

As of June 14, I don't see those suggestions anymore. FB must have tweaked this function.

Facebook is the new Big Brother.

We are not far from the idea of 1984. Confidential information about who you associate with and how you know them is being tracked, stolen and used by a "faceless" web site.

How Orwellian!!

Oh, it gets worse. I've got just about every privacy setting tweeked to make sure that Friends don't see my other Friends. Reason's pretty much as already stated, for example ex-girlfriends. Hardly want them all introduced to each other!

I set up a test Facebook account so I can see what's being shown to a Friend. Sure enough, the test account can't see my Friends list, but lo and phucking behold, ALL MY FRIENDS ARE IMMEDIATELY SUGGESTED TO IT! AAAARGH!

So I'm back to thinking maybe this is just too dengerous an arena for anyone who wants to keep friends separate.

Anybody recommend or suggest a way to press Facebook to NOT do exactly what I've just described?

Similar to "Secret Squirrel", I just setup a facebook account for the very first time (yes i am behind the times) without ever going near the find friends function, in excess of 250 friends were suggested to me, and they are people i know. I don't understand how, if i have never searched for friends, and never imported an address book, how they can find so many people i geniunely know.

Not Impressed, those suggestions are probably based on the people that have your email address in their contacts list and allowed Facebook to access those contacts. The behaviour sounds exactly the same as what my original post describes. Not only will it be suggesting those people, but it will also be suggesting their friends too.

I noticed this the other day too...after some thinking, I think anytime I email someone (or they email me) w/ a gmail account (I'm sure others do this too), their email address is automatically added to my contacts, and mine to theirs. I'm constantly removing people from my contact list. I wonder if I remove them from from my suggested list soon enough, if it will not suggest their friends...

And based on more trials with dummy accounts, I can now tell you it also collects addresses you manually type in to search for. And if that person's not on yet, if they later join using that email address, they'll be auto-offered to you, and you to them.

Who knows if they'll fix this or not. It's good for people with Really Simple Lives, but bad for anyone else. I actually kind of fear it. I mean, how about this, if it does introduction by mutual searching – haven't tested it yet though – two ex-bf/gf's search for a known email address of yours and are introduced. Well, that's ALL you bloody need! :-p

Here's the fix for this nonsense:

Give Facebook a DEDICATED email address. One that you use only for Facebook account purposes.

You could even make life a little easier and set the new Facebook-only email account to forward everything to your regular mail account, just to make sure you get all your FB notification mails without having to remember to log in to the FB-only account. You can use forwarding with most of the free services, and it's a breeze if you have your own domain with email service of course.

Sorry to double post but – are you all aware of this little chestnut too;

If you have set all your Friends to be unable to see your other Friends, all your Friends WILL be suggested to all your other Friends as a "Suggestion".

What the?? By setting them unable to see Friends, that's pretty clear you don't want them shown everybody else.

There IS no way to remain partially private on Facebook. Closest you'll get is to add no Friends at all, and use a dedicated email address.

Opens up the whole question of whether Facebook's actually a suitable thing for you to use at all if (frankly rather impressive) networking technology like this daunts you though. We all know what we signed up for, and there's always a Delete Account option. :-/

I have a strong suspicion that FB is using the Search feature to suggest a friend to you. And here is my proof.

Last week-end I bumped into a lady in the queue of Subway whose son played soccer with my son. I had not seen her for years and none of my FB friends are related to her. We did not talk about FB nor did I know she was on FB. The very next day I got her as a friend suggestion! The only explanation I have for this is that she went to FB search and typed in my name (I certainly did not do a search on her and, indeed, did not even know her surname. Neither is she on any of my email contact lists). Go figure!

You can remove this information.

Friends->Find Friends->Learn More
http://www.facebook.com/contact_importer/remove_uploads.php

Thanks Canna, I've added an update to the post!

Thanks Canna.

Something weird just happened here... a contact I certainly know I didn't invite to join Facebook received an invitation "from me". I don't know if any other contact has received it too, but it's not comfortable...

I thought I was going mad. About two weeks ago, my friend suggestions were filled with former coworkers and people I've met once at conferences and networking functions. It was kind of creepy to login and see faces that I've only met ONCE appear on this list. After confirming that I had no mutual acquaintances or mutual locations/employers etc. with these people, I begin to suspect that Facebook had hacked my email account. LOL.
  
Tonight I've learned that Facebook saved the email addresses from a contact list I imported over 2 years ago. From a business standpoint I understand why they've added the imported emails to suggestion algorithm (kinda), but I believe that it was implemented poorly (understatement).

IMO By default, old imports should have been removed or omitted from the suggestion algorithm. Then, they should have disclaimed on the 'find a friend' page that all imported email addresses are saved unless an opt-out box is checked. But that would be too much like right.