= the number of connections that an individual can hold. 
"Whereas the group thresholds ... define the limits placed on community group size, the personal limits described herein instead define the limits placed on how many people an individual can know with various degrees of intimacy." (http://www.lifewithalacrity.com/2008/11/personal-circle.html?)
The material below is from Christopher Allen.
The Support Circle
"This is the number of individuals that you seek advice, support, or help from in times of severe emotional or financial stress. In most societies, the average size of an individual's Support Circle is 3-5. The people are the core of your intimate social network and most typically are also kin. In sociology papers this is often called the "support clique"." (http://www.lifewithalacrity.com/2008/11/personal-circle.html?)
The Sympathy Circle
"This is larger then the Support Circle — it is the number of people that you go to for sympathy and also those people whose death would be devastating to you. The Sympathy Circle typically is in the range of 10-15 people, but can vary widely from as few as 7 to as many as 20. The Sympathy Circle often may be made up of kin, but usually includes some peers as well.
In sociology papers the Sympathy Circle is also known as a "sympathy group", but I wanted to avoid the term "group", as it is implies that all the members of a Sympathy Circle are connected. Instead, members of your Sympathy Circle will have additional people in their own Sympathy Circles that are not part of your own.
An interesting issue with the Sympathy Circle is that as a personal limit, 10-15 is a typical size. however, if you bring them all together in one place, they will likely become a Judas-Number-sized group, with all of the problems associated with that size." (http://www.lifewithalacrity.com/2008/11/personal-circle.html?)
The Trust Circle
These are the people that you have some type of intimate connection to. One study measured it as the people that you would send a family Christmas card to, while another simply tested emotional closeness.
In pre-Friendster days the Trust Circle would be those people that you considered your "friends", however today the meaning of that term has begun to change. In my own usage, your Trust Circle are people that you have strong ties to and that in some measure you can trust. I have also called the Trust Circle your personal "intimate social network".
The size of different individuals' Trust Circles can vary widely (40-200), but some studies show that the mean is on the low side of 150. This has led a number of researchers to compare this number with the Exclusive Dunbar Number of 150. However, I believe that this is a mistake; they are related, but in today's society members of your Trust Circle are rarely in the same mutual group." (http://www.lifewithalacrity.com/2008/11/personal-circle.html?)
The Emotional Circle
"I personally define your Emotional Circle as the total number of people that you can have some type of non-mutual emotional connection with, most likely spread across numerous groups of all sorts. You "like" them in some way, but do not necessarily have to have strong ties to them.
In academia this threshold is called "social channel capacity". A study using two different methods to estimate, both suggest that it falls right around 290. However, I like to describe this number as "just short of 300." As I wrote in Dunbar Triage, many people confuse this number with the Dunbar Number (and in fact I have in some of my older pieces). However, like the Trust Circle, it's a distinct entity.
Emotional Circle size can vary quite a bit from individual to individual. Some people might have half the average capacity, and others considerably more — which is much more variation than you see among the sizes of smaller personal thresholds." (http://www.lifewithalacrity.com/2008/11/personal-circle.html?)
"Outside of our Emotional Circle is a larger, more tenuous circle: those people whose faces you recognize, but who you know nothing more about. These are your "Familiar Strangers".
Studies show that the percentage of familiar strangers in your vicinity has a real impact on your willingness to take risks. If you are in a new place with no one that you recognize, you'll avoid eye contact and will generally be unwilling to approach strangers. In a place where there are a lot of people that you've seen before (say in your favorite cafe, at a conference, or in the lunchroom of a large company), you'll be much more willing to take risks, such as asking questions, or sitting down next to someone to eat lunch.
I haven't been able to find any studies to show how many people that we can recognize, but for some people it is much larger than the number of people in your Emotional Circle, probably well over a thousand. However, there is also a lot more variance: some people are face-blind or near face-blind, and have a difficult time even recognizing friends." (http://www.lifewithalacrity.com/2008/11/personal-circle.html?)