Think of pre-computers (that may be hard for some of you) back to the day of magazines and binders. We would pull out something that we wanted to remember and put it somewhere safe to keep. 

When Pinterest came along in 2010, we now had a place to take down that idea from online and tuck it away into our virtual binder (what Pinterest calls boards).

For you as a marketer, this is where you will put all your content to help tell Pinterest and followers what your content is all about. Basically, what section of the binder are you going to put your best ideas.