This could be amazing. According to Google’s Eric Schmidt, every product on Google will eventually move to support some of the Plus infrastructure, such as Circles.
I think Paul Allen summed it up best:
This is breathtaking. I have already built 54 circles. I can imagine being able to instantly share anything I find on Google News, Google Reader or YouTube (or any any web site that I access with Chrome or my mobile phone) with any of my carefully designed Circles. This is a knowledge worker’s dream. The signal to noise ratio in our various streams will improve dramatically.
Not only will this make those other products more useful to us Google+ users, but it will drive more of those users to try out Google+. It really seems like a brilliant move from Google. What do you think?