Hindsight is 20/20 for Google+ Circles
Use Google+ Circles The Right Way
What's a circle anyhow? Consider a sociological view.
My childhood friends don't care about IPO's and Tech news, but my business contacts do. My mother doesn't need to hear about my transgressions from last weekend's epic party. Likewise, neither does my boss...
Conversely, my business contacts would probably be annoyed at the absurd amount of pictures I post of my dog (My mom loves them).
Circles allow us to 'speak' to the correct audience in the correct way with content and engagement that matches the culture of that group.
These relationships form social circles. There tends to be some, but little overlap in their members.
Here is where it gets really neat.
These social circles are self organizing, self governing and well defined social norms. They have unique "micro-cultures" defined by the members of the group. We talk differently, we behave differently, we share interests and values unique to that particular circle. Millions of years of evolution has created these inherent biological responses to improve survivability by allowing the formation of empathetic communities that work together towards a common goal.
A Brief History Of Web Based Social Organization
The correct way to create an online social network, is to model it after real life. But we (developers of social networks) didn't get that right away. We had to go through a sort of learning process. Excluding early forms of online social organization (BBS's, IRC, Chat Rooms, Forums), it went something like this:
MySpace (a failed attempt at social organization), to
Twitter (an introduction to one method of communication useful to social groups but suffering from a high signal to noise ratio), to
Facebook (who only much later understood the social paradigm and 'tacked' groups onto a mature platform).
What Happens To Facebook?
Facebook was one huge step forward, but it failed in one fundamental way. While they had correctly implemented the notion of a social circle via groups, they didn't teach anyone about it. It was treated like some sort of complicated security feature and most users failed to adopt (or understand the importace of) it.
The 800lb Gorilla
Google+ took the lessons of hindsight to correct on this paradigm. Google took 'circles' and made it the core of its platform. Users are confronted with circles the moment they begin using +.
There's work to be done... Early adopters of Goolge+, are struggling to understand how to use this modailty and begin to fall back into the habits of old.
Some use it like Twitter. Some like Facebook (shove all their contacts into a single group or completely ignore groups). Some don't take the time to think about their content's (comments, posts, media, etc) audience before posting it.
While we inherently must rely on our underlying trust and judgement how we organize and engage with our circles, what we're ushering in is (hopefully) the adoption of a new way of thinking about the content we put on the web and for whom.

