This way of communicating is clearly superior to Facebook's "one-message-fits-all" approach. Not only will it be useful for communicating with friends and family, but because it lets you target who gets which types of messages, it can be useful for work as well.
You are alerted about new messages via both email and a small notification button at the top right of the main window. (That notification also appears on your Gmail window.)
However, communicating with people is not quite as straightforward as it at first sounds, possibly because Google+ has a limited number of members at this point. For now, most of the people you put into circles can't communicate with you directly on Google+. Instead, they'll just get an email, which diminishes the usefulness of Google+ considerably. Until Google+ enters more widespread distribution, it will remain more a testbed than a useful communications tool.
Sparks, Hangouts, and Photos
Circles are the core of Google+, but there's more to the service as well. Sparks brings together the best of Google and social networking -- it's a simple way to find and share content that interests you and might interest people in your circles. (I assume that it's named Sparks because it's designed to spark online conversations.)
You can share any content in Sparks with all your followers or with specific circles or individuals by clicking a Share button.
Click on the Sparks button (on the left side of the screen, just below your Circles list), and you'll come to a list of general topics, such as Cycling, Fashion, Movies and so on. Click any of the topics on that list, and you'll see a stream of content related to the topic, including blog posts, news articles and videos. You can also create your own topics to follow by typing in a search term, clicking the search button, and then clicking a button labeled "Add interest."
Another feature, Hangouts, lets you videoconference with others in your circles. You can create a hangout and either invite others to join or just wait for others to join; a notice that you've created a hangout will display in the stream of people in your circles.
Those who enjoy videoconferencing will find this a convenient and simple way to video chat with friends. It's exceedingly simple to use, and only requires that you have the right equipment -- a webcam and a microphone. (If you don't have a webcam, you can participate via audio only.)
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