The Read Later Circle trick.
I've been using G+ for years now, and one trick I learned early on from another G+er was how to save content to read later. It's really quite simple:
Create a Circle called something like Read Later. I call mine Read This.
Don't add anyone to the Circle.
Whenever you see an interesting post that you don't have time to read at the moment, share it with your Read Later Circle.
At any time, you can filter your stream by Circle. If you filter by the Read Later Circle, then you will see all the content you shared to yourself. Once you've read it, you can delete your own post.