some popular trading strategies are based around VWAP. A very basic strat is to short the price of an instrument when it drifts too high above vwap, or to buy when it gets too low below vwap. One might ask, "how do you know when a price is too high above of below vwap?" It's based on statistical variances.
another is the buy order book vwap imbalance. a vwap is calculated for the buy-side of the order book, and the sell side as well. Think of macd's. When one diverges away from the other, you take that trade. Say the buy vwap starts to increase in slope, whilst the sell vwap is flat to negative in slope, you want to get with the trend, which is to buy, buy, buy.
Contrarian strats are put to use as well, easy concept, just fade the moves that are at statistical extremes (think of a bollinger band fade, for a simple example)
The truth is that many hedge funds have a treasure trove of strategies to use, that have been previously discussed, like arbs and the above info, and it lets the black boxes choose which strategy to use when the situation is deemed appropriate.