What is Distributism exactly?

The first gazillion times I heard the term Distributism I asked what it was precisely.  I never got a good, simple explanation of the concept and always got the feeling, from the person using it, that I should already know what it is, that I should have an understanding of what he or she meant by it (sorry, I like some guidance when I'm confused).  Here's a good entry.  Uber Catholic commentator Mark Shea provides a good example / contrast.    It emphasizes subsidiarity, a concept in Catholic Social Teaching.  So it's a very Catholic thing.  I'm down with that of course.  So Distributism:  I'm not agin' it.  I'm fer it.