Maybe it's because there are a handful of people who are trying to keep the price from bubbling to far out of control and also at the same time selling a little sliver of their hoard. Someone with a million bitcoins could put up walls all day and by the time we got to 50 they could have made millions
that, plus you can often observe secondary, smaller, not so obvious walls popping up as a support, when the price bounces back on the next wall on top. If you're strong enough really to dominate the market movement, this could be a nice strategy for making easy money, and /or a strategy to get into the market without driving the rates up too much. Place a huge wall, watch the market bounce back, absorb some of the movement at a lower price, let those suckers buy into the wall above until you've made enough profit, pull the wall. Rinse repeat.PS: of course the risk is when suddenly another guy with even larger balls swallows your wall....
