The majority of coins are sold OTC. Anybody who does a lot of big trading knows this.
But how are coins valued? You guessed it, most of the time using the price on BITSTAMP.
What does this mean? If you are able to control the price on Bitstamp, you control how much Bitcoin is sold for elsewhere.
Let's say you want to buy a block of coins from an exchanger, OTC. If you are able to manipulate the price on Bitstamp with a sell/buy wall, you directly affect the price you pay from the exchanger.
Bitstamp's volume is tiny in comparison to the OTC market. Their only real function is determining a VALUATION of Bitcoin as a whole. The market depth/volume on Bitstamp is a joke in comparison to how much is traded OTC daily.
Control Bitstamp's price, you more or less control the market price everywhere.
Make sense?
You are wrong! You can't control the market but you can influence it. A market is about buyers and sellers so if you put up a massive wall then that price will stick until the wall is broken through.
Yes this will have an effect regarding other exchanges but then it opens the door to Arbritage.
Last night a 30,000 wall at around 3.00 am. The price stopped for about 4 hours and then bounced 50 points when it fell.
How, exactly did that deal control the market?