How Facebook “suggested friends” actually works


To connect its users more closely, Facebook has a feature called Suggested Friends and in this guide we’ll explain how it actually works…

If you’ve been on Facebook in the last 12 months, you’ve seen these “suggested friends” special feature. You get a notification, click on it and Facebook has a suggested friend for you.

But how does this function actually work? Do you have to know the person? Or is it just a random guess generated by Meta’s sprawling algorithm? More importantly, you can “play” this feature to make it appear
in more people’s “Recommended Friends” list?

This is how Facebook’s Suggested Friends feature works.

Officially, Meta’s stance on how Facebook’s Suggested Friends feature works goes something like this: you must A) have mutual friends, B) have similar and/or complementary profile or network information, or C) have similar interests and/or activities Facebook, either in groups or by tagging on a photo and/or location.

That’s the official explanation for how suggested friends work on Facebook, but in my experience – admittedly, it’s pretty limited; I rarely use Facebook anymore – there’s more to this feature than Facebook reveals in its official description of how it works.

When proposed friends get creepy

Here’s an example from Reddit of one man’s experience with Facebook’s suggested friends.

The first thing that was strange was that it suggested me my SO’s Facebook page, who once created a Facebook a few years ago and then gave up the account and hasn’t been on the page since. We met on OkCupid and we don’t have mutual friends. I have some pics with her so maybe it did its facial recognition thing?

Weirder was earlier today when it suggested I add a girl I dated a year ago who I had never contacted on Facebook, had no photos with, and didn’t even remember until Facebook told me about it me. We don’t even live in the same state.

I have never used any type of Facebook or Okcupid app on my phone. The only thing I can think of is that Facebook was digging into my Okcupid account looking for people I messaged? But then I haven’t had an okcupid account since October.


As he points out in the post, Facebook appears to be making connections between him and other people without actually having the information needed to do so, leading to the obvious question: How does Facebook do that?

One theory, and I think this is the most plausible one, is that Facebook uses your search history on Facebook to make suggestions for suggested friends, so in the example above when the guy was searching Facebook for the girl he just was on a date with – whether it was a year ago or three years ago – Facebook will know and have this information.

An algorithm never forgets, all it does is grow and evolve by learning more and more about you. In this context, the algorithm simply pulls information about a user from its database and uses it to create connections it deems useful within the suggested friends.

Theories on how Facebook’s suggested friends work

phone numbers

Another theory about how suggested friends work revolves around phone numbers. Say you give someone your phone number, maybe you met at a bar or on a date.

When that person uses their number on Facebook, Meta continuously scans their contact list for new connections. Once it finds a new contact, in this case you, Meta’s algorithm has your details and adds you to the other person’s suggested friends list.

fingerprint on canvas

Another theory revolves around the idea of ​​”canvas fingerprinting,” a method of tracking users online without cookies. Well, that’s pure speculation, but a company Meta’s size almost certainly uses a Raft of tracking technology To monitor its users, it stands to reason that it might also use its own proprietary version of canvas fingerprinting.

But what is canvas fingerprinting anyway? Here is a brief overview:

Canvas fingerprinting gets its name because it tells web browsers to draw a hidden image, and each computer produces a slightly different, unique image. Like a fingerprint. A creepy fingerprint who wants to follow you online.

Once your browser draws the hidden image, the information is passed to the website. It uses your unique picture to assign a number to your computer and create a user profile to better sell targeted ads. Canvas fingerprinting was invented in 2012 and a company called AddThis developed code that is used 95 percent of the time.


If Facebook uses some sort of version of this technology, it could put it to good use to create connections between two different accounts. Again, this is just a theory – Meta has never confirmed this – although we know that Facebook, like Google, uses fingerprinting techniques to track and analyze its users.

They both looked at each other’s profiles

One of the simplest ways that suggested friends might work relates to how you actually interact with Facebook. Here’s an example: Suppose you happen to remember someone from school, so you do a Facebook search to see if they have a profile. If you find them and go to their profile but don’t add them, Facebook’s algorithm will make a note of it.

Suppose the person you were looking for has the same idea: they remember you and then do the same thing, look for your profile, click on it but don’t add you. The algorithm assumes you’re both interested in each other but shy or whatever and sets about making the connection by adding you to its suggested friends list and vice versa.

For example, prior to writing this article, based on a hunch, I decided to see if I could change how suggested friends work by searching for and visiting a few profiles of people I know but don’t date am connected on Facebook. I waited a few days and sure enough, some of them showed up in my suggested friends list.

Facebook spies on you all the time

There is a popular belief that by installing Facebook on your phone You are tracked 24 hours a day, 365 days a year. This theory states that Facebook uses your phone’s microphone to listen to you, your camera to spy on you, and your phone’s GPS to know where you are and when you are interacting with other Facebook users at all times.

Facebook – sorry, Meta – has specifically denied this. But there are still thousands of reports on the internet suggesting the opposite. I mean, check out this little ditty from a Reddit user:

Something even scarier happened to me today. I met a girl at the club last night. We had a fairly short conversation. I didn’t even get to know her real name. Just a nickname. When I opened my FB for the first time the next morning, it popped up as a friend suggestion. First on the list. It sent shivers down my spine. I don’t know her from before. We don’t have mutual friends. I never looked for her on FB as I have nothing on her. I don’t use FB on my phone. I don’t check in It’s possible she searched me, but I don’t think she found out my name either. It was just too loud in the club. That’s the only plausible explanation though, since that sort of targeted suggestion is out of reach of FB data crawlers (I suppose). Other explanations would be too far-fetched, even for my odd taste.


Or this:

Something similar happened to me, I met this guy on vacation, we don’t have mutual friends, he’s from out of state, I didn’t have his number, but for some reason he came up as a “suggested friend”. Strange.


Of course, we’re talking Reddit users here, so all bets are off when it comes to the legitimacy of these claims. But if we’re playing devil’s advocate here, something could very well be afoot – something that isn’t listed in Meta’s official stance on tracking and monitoring its users.

I mean, we’re talking about meta here, not a small startup. It has almost certainly employed exotic technologies on its platform that are not publicly known. Much of this can be – and is – explained as “just stuff the algorithm does,” but an algorithm is only as good as the data set it’s fed.

So the bigger question here is maybe What technologies does Meta use to create its data profiles? We know the ones that are used officially, but are there “other” less official technologies? My best guess would be, yes, Meta uses exotic proprietary tracking and surveillance technology, but we probably won’t know about it until the next Cambridge Analytica-style scandal falls.

Richard Goodwin

Richard Goodwin has been a tech journalist for over 10 years. He is the publisher and owner of KnowYourMobile.


About Author

Comments are closed.