Let me explain something real quick from my perceptions of my friends.
In high school, I wasn't part of any group of friends. I was acquaintances with a lot of people, from various stereotypical cliques of people. I got a job and became close friends with two people in particular, and we did a lot of things together up until two of us quit. I found that I preferred having a closed group of friends who knew a lot about me, and who did a lot of things with me, than having sporadic friends here and there with only a small percentage of common interests.
I'm someone who would rather have a few close friends than have a bunch of friends who know very little about me. I'm someone who, when out in real life, would rather hang around two or three people in particular and experience things together. This would be my core group of friends. I imagine mostly everyone here has friends that they consider to be a core friend. Someone who would wouldn't dare remove or replace. Sort of like a best friend, I suppose. I guess for me I prefer being in a group of friends, opposed to having a bunch of friends that associate with each other, or worse, don't know each other. I don't consider the group of friends I have offline and the group of friends I have online to be cliques, though, despite often wanting to keep them closed up to other people because I want to maintain the relationship and friendship that I have with the current members of the group, so I guess this really serves no purpose other than wasting time.
Online, I have two main branches of really close friends that tie into three individuals in particular. One of them consists of only one of my close friends, the other consists of two of my close friends. These three are the best friends I have on PC. For one of them, I associate them with a few other people, consisting of a lot of members that I have a great deal of respect for. One of which used to be closer than they are now, but drifted. I group them all, in addition to the one friend that I consider one of my best friends, as a group. Not particularly a clique, but a group of people (in my mind) that I wouldn't want to upset and intervene in. Meaning if they were a club of some sort, and I got an invitation in, I would decline. The other two friends are friends that I've had for a longer time than the other one, and have always considered us to three to be somewhat of a group of people who would tell each other things a lot. Sometimes one of us wants someone else to be inside that circle, and most of the time the other two often state how we/they would prefer it to be just the three.
I'm very terribly confused after typing that. :/ I was a member of two cliques here at PC, and my time in both of them wasn't as much as I was expecting. My first clique was something that happened gradually when I first joined, then developed into this small club sort of thing, and then became really closed off to inviting others... I think. My second clique was something I wanted to be in for a long time, and once I finally got in, I felt like a complete outsider to all the other members. I still talk to most of them individually now, but I know now that if I met myself from back when I was longing to be in that group, I would tell myself not to bother and that I already talk to most of the members that are in the group as it is, and it isn't anything all too special when they're all put into a group, since I don't share the same interests as they do in a group setting.
I think cliques are sort of natural. Not in the middle school sense of it, but in the sense that you've got a small group of people you're attached to, and adding new blood into it just complicates things 2 out of 3 times.