Select which aspects you want to see in your stream
What I'm proposing is to be able to say which aspects I want to see in my stream page.
This is a feature that I find very useful in G+, particularly for those who care about what is displayed in their stream page and how relevant it is.
Here is a G+ screenshot, as you can see, you can choose whether or not to add the circle into your main steam:
This allows to have a difference between adding someone in our aspects and actually following him. Sometime you just want to add someone in order to send MPs to this person, but you're not interested in what he is posting on a day to day basis.
I think that is part of the solution to limit our stream to be "spammed" by unwanted posts.