A few further thoughts about clutter:
The laws of thermodynamics mean that heat flows from higher concentration (i.e., hot) things to lower concentration (cool) things. Eventually, everything settles at one temperature.
In the same way, eBay allows a kind of crap-o-dynamics. Stuff moves from high concentrations to lower until all the world's junk is where it's supposed to be. If it weren't for people moving, changing jobs and dying, eBay would put itself out of business.
And speaking of out of business, note that clutter itself is becoming obsolete, at least in the physical sense. Books, newspapers, magazines and even notebooks and scrap paper are being replaced by digital versions. (Ha! Just try wiping your mouth on that iPad. Not very absorbent, is it?) Of course, you can have cluttered disk drives, the cloud is replacing them too!
Not a bright future for us pack rats.