Dunbar's number is the theoretical cognitive limit to the number of people with whom you can maintain stable social relationship at a given point of time. These are the relationships in which people not only knows each other but also can figure out how another person is related to each other.
Dunbar says this limit is directly proportional to the size of neocortex. For Human beings Dunbar's number is approximately 150.
Ever since Dunbar has hypothesized this number after observing many primates and past human societies, people have taken this number to be the ideal size of community.
You have only one neocortex in your brain and you cannot split it for several communities, i.e., between online and offline world. You can amass thousands of friends on facebook, twitter, linkedin, google… but won't they consume the processing power of your neocortex in your brain and you just can't refresh it on different network, nor can you divide it between online and offline world.
Your network of friends on social media and your friends who count among Dunbar's 150 are not the same. You can walk through a crowd of millions of people and also communicate with them, but they are not into your actual network! Here the processing power of your brain limits the actual size of your near and dear ones.
People have talked about developing weak ties to beat the limit of Dunbar's number. But, does it actually beat it? Had it been really true, Dunbar's hypothesis would have shown no link with numbers, because differences in likeability, affection and love a person shows for others is a known fact. So, had it been possible, Dunbar’s number would never have existed, because given this possibility, where strength of ties is different for every individual or animals, would have given Dunbar different figures and in that case he would not have hypothesized a limit.
So, whether weak or strong, if they are consuming the processing power of your neocortex and tie is worth calling mutual and engaging association, they would count among 150! You cannot decide upon warmth of the relationship that may develop as a result of numerous personality traits, sometimes anatagonistic and sometimes attracting, and, let us not forget, the Dunbar's limit is consistent with observations in many animals and past human societies.
Hutch Carpenter has an interesting post where he throws light on what this Dunbar's number actually counts, and how to cultivate more friends through Scooble's number. As he shows in the diagram, "You connect when interests and attentions coincide, Drive by interactions." He has rightly pointed out, you can amass more friends through this, but you cannot violate Dunbar's limit. So, the moment tie becomes closer enough it will come under Dunbar's limit. If you have achieved Dunbar's limit, then your gain might be loss somewhere. So, someone somewhere might be moving out of your network, if you are getting closer to someone.
Rather than trying to beat this number, just identify who are your 150. Have you reached this limit? Answer in most cases would be no. Have an action plan to raise your real network to this limit. Reaching this limit would mean you have reached the peak of your networking potential.
People within this limit don't only know you but also who others are known to you, and mutual sharing and caring goes on. If you are on Twitter, make a Dunbar Twitter List, If on Google Plus, dedicate a Circle for Dunbar Limit, to practically do this and see the outcome. Here you would understand the real dynamics of Dunbar Limit and practically see How people are coming in and going out and what you need to do to raise this circle to the maximum possibility.
An important point to ponder here is, the number itself is not the hard limit. It is just a projection. Limiting factor is the size of your neocortex brain. So, the number itself may not be accurate. It might be higher or lower than what is quoted, but important point is the existence of this limit, and its relation with size of the neocortex in brain.
So, it may not be limited to networking alone but in many other things where neocortex’s processing power is involved. Regarding this number as limit, has led us to see the magic of limited space messaging when it is close to this limit.
Is it mere coincidence that twitter allows 140 characters, and adwords ads have 130 character limits! Isn't it because honoring this limit leads to the most possible exciting experience where each character we write sums up to the highest possible and conceivable form of intelligence, that can be experienced at a glance!