Ann: Gas Shows at Borba 1-7, page-206

If you have a large holding and want to accumulate more at a cheaper price you put a large sell order in a bit above market price to indicate weakness in the stock. Same as false bids a few pips under. People trying to make the stock look loved. When the price gets close the sells or bids they are pulled as they were fake. Market depth is just a very loose indication of sentiment. Chi-X and ASX aren't shown on all platforms so the depth is often incorrect also.