What are Google Circles?

Have you ever received an e-mail indicating someone has “added you to their Google Circles?” My response is to check out their profile, and if they don't appear to be a serial killer, I accept their invitation. But I'm not really sure what I'm signing up for.

I thought, who better to ask than Google? https://www.google.com/+/learnmore/circles/

After reading through the website, I came away with the understanding Google Circles are kind of like a polite “alert” mechanism which allows those in the “Circle” to receive posts that have been shared with other members online.

There appears to be an option which allows the person generating the post to share it with everyone, or just a few select people. Conversely, the program also allows users to create different circles to receive different kinds of content.

How does all this affect me? I'm still not sure. I continue to accept invitations and select the “public” option when I post on my blog, but whether or not anyone is alerted to the fact remains a mystery. Nonetheless, I believe Google has it's heart in the right place, creating a program that, when understood and used correctly, could be a great way to communicate with different groups of people.