The reason why I personally think Google+ usage is leveling off is because Google has been adding user engagement features like "What's hot on Google+" or the Y

The reason why I personally think Google+ usage is leveling off is because Google has been adding user engagement features like "What's hot on Google+" or the Youtube pop-over search. Why would they clutter the screen with this kind of stuff if they claim they have such a large user-base? Probably because there is a large number of people who don't have anything to do. For me at least, I can definitely say I feel the same way about Google+ as I did about Buzz and Wave. They were kind of cool to mess around with in the beginning but eventually I forgot about them. The only reason why Google+ seems to be sticking around a bit longer is because of how visible it is on the top navbar as well as how invested Google has been into making it into some sort of central hub for all their products. But who knows maybe it'll be like their search engine and gain quality over time. Doubtful though..