I ripped this off Jia Xuan's blog, i think its kind of interesting and meaningful. Yea thanks jx

Market Structure - 4 types of market
[Hmm beware all this is crap :) ]
Like markets, some people really have a "friendship market" of perfect competition. They have "no barriers to entry", which means that it is very easy to socialize with them because they do not form cliques with people that are hard to join. They have many friends because it's so easy to be friends with that person, and he or she is likely to have a great personality to attract everyone. However, because of the fact that they treat every friend equally (equity), they are unlikely to have very good friends.Hmm but I believe this is highly theoretical (like how the lecture note says). This is because it is impossible for people to not form cliques and have better friends, but this is a basis for comparison and analysis.

The next friendship structure is monopolistic competition. This is pretty similar to perfect competition because the barriers of entry are not high - it's easy to be the person's friend because he accepts most people... but somehow he or she only accepts people with "differentiated friendships", people that are unique and are worth making friends with and perhaps reject some with bad personality.

Oh... and we have oligopolies too, its probably the most common type of friendship structure. I guess this is pretty obvious, there are high barriers of entry because there are cliques formed (probably between 3 to 6 people) so it is pretty difficult to be good friends with the person. You may be friends with the person but it may take more time and share experiences to be a good friend with the person. Generally, you would feel an aura around the person that makes it hard to talk to him or her.

Lastly, a extreme friendship structure would be monopoly, very simple to understand actually... one best friend, period. No one else can be very good friends with the person hahaha, since the aura is super strong!