Robintrack keeps track of how many Robinhood users hold a particular stock over time. Most of the stocks at the top of the list are popular longs for retail investors and popular shorts for hedge funds. It generates charts showing the relationship between price and popularity and compiles some lists using the data. One of the most useful things that you can do with the data that this site provides is to figure out how people are reacting to moves in the market. Depending on if people are buying the dip, getting onboard during a pump because they think it's going to go higher, or taking profits, this data lets you observe each of those different situations and plan your own trading accordingly.