The other day, I talked about the “real” Twitter: the sparse subgraph of meaningful social relationships buried in the far denser follower graph. Well, it turns out that Facebook’s own “in-house sociologist” Cameron Marlow has documented a similar phenomenon on Facebook:
The average male Facebook user with 120 friends:
- Leaves comments on 7 friends’ photos, status updates, or wall
- Messages or chats with 4 friends
The average female Facebook user with 120 friends:
- Leaves comments on 10 friends’ photos, status updates, or wall
- Messages or chats with 6 friends
The average male Facebook user with 500 friends:
- Leaves comments on 17 friends’ photos, status updates, or wall
- Messages or chats with 10 friends
The average female Facebook user with 500 friends:
- Leaves comments on 26 friends’ photos, status updates, or wall
- Messages or chats with 16 friends
Students of sociology have long been familiar with Dunbar’s number, which Wikipedia defines as “the theoretical cognitive limit to the number of people with whom one can maintain stable social relationships”. Others have proposed different limits, but everyone seems to agree that the number is less than 300–something that you might not know from looking at the follower / connection statistics of online social networks.
Of course, this cognitive limit reflects attention scarcity. Wouldn’t it be nice if online social networks did too. I’m trying!
The Noisy Channel 
6 replies on “Dunbar Lives!”
Interesting numbers but I think you missed some significant part of that – what time span are these numbers measured over? I would think that # of different people you connect with online would be closely correlated with how much time you spent online, and the alternate explanation is simply that 500-friend people are more intensive users of the system overall.
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Here’s a link to the Economist article cited by the blog post–no mention of the time span. It’s a good question.
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@Edward: The numbers cited are for a 30-day activity period, specifically to be comparable to other studies (such as Kossinets 2006). I will be posting some more details about the data we pulled on my blog within the next week.
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If you blog about them, they will come!
Cameron, thanks for the clarification. I’m looking forward to those details, and I’m sure many readers here are too.
I’m not sure if you’ve had a chance to look at related posts, but I’m on something of a mission to promote the value of the more meaningful, sparse social networks hidden inside the superficially dense ones. So naturally I’m excited to use your research as ammunition in pursuing that cause.
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this is exciting. It’s one of those datasets that i’d like to spend ages on if i had access to it all (like my post on Viacom vs YouTube – http://maxlwilson.blogspot.com/2008/07/best-search-dataset-ever.html).
I’d be interested to see more on other facets of correlation, such as people who have friends vs people who have mainly colleagues on facebook, and people who log on daily vs people who log on weekly etc.
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[…] from Twitter is more of a challenge. I follow 100 people, which is about the limit of my attention budget. I use saved searches to track long-term interests (much as I use web and news alerts), and I […]
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