An increasing body of research is suggesting the humans have evolved for a group size of about 150. Known as “Dunbar’s Number”, the idea is that in groups larger than this size our efficiency breaks down. I think the working assumption is that we cannot track more than this number of people without losing a lot of resolution, and that we work best when we have a good and high resolution relationship with people: http://www.commonsenseadvice.com/human_cortex_dunbar.html
Joe Duck
Have Blog. Will Travel. Vaccinate!
Joe Duck 
Odd. The Hutterites in the USA’s northern plains areas tend to establish a new commune when their numbers reach 150 households.
FG – wow, interesting. I have not looked into this much but it does make sense that evolution and/or brain limitations could create an optimal group size.
Hmm – I wonder if online social networking, which often creates *huge* groups of thousands, will mess with out minds even more because of this.
When it comes to ‘Social Networks’ I am reminded of the famous statement concerning The Holy Roman Empire: Its not holy, its not Roman and its not an empire!
Ofcourse a decline in efficiency does not mean a decline in use: the Qwerty keyboard has never been efficient but Dvorak will never replace its use.
Now within a large social group, one encounters perhaps a 150 limit, I don’t know? The army can number in the millions but the soldier experiences his sergeant more often than anyone else.
Digg networks with political causes value their large numbers but their clout is probably expressed through a small cadre of leaders.