It's a problem, for sure!
I've done a couple of things to try and curb the flow. Hopefully, some of the tips can work for you, too!
-I try and define the space. Basically, I picked what kind of space I could allow for pins, and what that space would look like. I try and stay within those numbers.
-My space is basically one wall in my studio, and one wall in my bedroom. On that wall, I bought a kallax cube system from IKEA, and I put my binders in the cubes. Then, on top, I put the heavy cork boards. Then, on the wall, I hang the more light weight frames. I have a separate shelf for jumbos that I don't want to take out of boxes. That one has been tricky to display. I also have holiday boards that I bring out for that holiday only. My bedroom wall is a little different. I have a large etegare where I put frames and sets (think Designer sets), and then around them I put some of my coutre de force or Jim Shore figures. Works really well, but it's more of a display shelf for lots of Disney collectibles instead of "pin storage".
-I put large, eye catching pins on the boards, and park pins tend to go in the binders. Basically, anything that would be a waste to put on a board anyway I just put in binders. Disney auctions, ds.com, WDI, and DSF go on boards, usually.