How does Black Friday work? On days like Black Friday, everyone rushes out expecting huge savings on everything they buy. The level of demand seems to reach ludicrous levels, and one would expect smart merchants to react by increasing all of their prices in response to demand.

Yet year after year we see videos of people beating each other up and trampling each other on Black Friday in a display of seemingly mindless consumerism. 

Is Black Friday really just a marketing ploy that creates the illusion of savings where really none exist? Has the market just not caught up with consumer behavior? Or is there another mechanism driving Black Friday?
Gary Becker's work on Social Demand probably has something to do with the phenonmena.
Becker basically asked why some popular places consistently seemed to underprice their goods. For example, concerts often sell out very quickly and fancy restaurants in the middle of a busy suburb might be often crowded. These venues could raise their prices, but the basic idea is that the demand for a good may not be independent of other agents' demands.
So demand may be dependent on how much other people also demand the good; you might enjoy going out to eat at somewhere that always seems popular than somewhere that gets less traffic, or you might beg your mom that you just have to go to that popular concert by [insert cool band here], specifically because all your other friends are going. Additionally, social places like restaurants and concerts often have customers who usually or only go in groups, so you could see how that would incentivize fiercer competition among these venues.