It's really the only way to trade and it occurs everywhere. The problem is, for example
@Tradex is only applying it to single instruments. That's a mistake.
Mean reversion trading is far better when traded as a
spread. Put simply, if two highly correlated instruments (futures, stocks, etc) are suddenly in disagreement you can long one and short the other collecting the spread eventually. Under the assumption the disagreement is a temporary shock (and certainly this would be probable with good data) then the legs of the spread will revert to their long term mean allowing you to close out the position and collect the spread. There's math involved here regarding cointegration arising from a linear combination of time series that is interesting but unimportant in practice.
Good enough makes money not mathematical purity.
When you have statistical backing the trading is far more consistent. Yes, you're sitting on your hands forever waiting for a break in correlation, but when it happens the probability of taking home the spread is very high. Professional futures traders have used this technique for decades. There are several other examples of mean reversion - almost anywhere seasonality exists.