150 is not the optimal group size, nor the maximum group size.
150 is the number of people, according to Robert Dunbar, you can sustain meaningful relationships with at any given time.
People misuse this number. It doesn’t mean you can have 150 good friends in an online community. It means you can sustain a maximum of 150 meaningful relationships in your life.
After you’ve tallied up your family, college buddies, work colleagues and other associates, you don’t have many vacancies left for friends. But it gets worse. The true number is probably much lower than 150, perhaps as low as 60.
You’re not just fighting for a share of your members’ time, you’re fighting for a share of their friends. It’s easier than ever to interact, but we’re not interacting with many more people just because we can. Stimulating interactions is futile without securing some of those friendship slots.
Real friendships still involve real stuff happening. The best way to facilitate friendships is by stimulating shared events, emotional experiences, self-disclosure and reciprocity.



Richard -
This is right-on! Too often I find NGOs/charities/campaigeners forget these dynamics - namely - how many of your exclusively online 'friends' do you have any kind of real relationship with?
If the answer is few-to-none, as I would guess it probably is for most of us, what kind of influence/sway do you think you have with them (or they with you?), if the entire basis of your relationship is an avatar and some 'about me' text?
If you want to build an effective online community, you should (as much as possible) provide the chance for people to meet and interact in the real world. This greatly improves the odds of developing meaningful links, and thus strengthening your online community. Then, when we get back to the message boards and social networks, those avatars are real people, no longet abstract ideas...
As none of us live exclusively online, how can we expect someone we only know online to compete with our real world friends and aquaintances?
Posted by: Liam Barrington-Bush | Monday, 17 August 2009 at 10:14