TRIX was invented in the early 1980's by Jack Hutson who was the editor for Technical Analysis of Stocks and Commodities magazine. TRIX is calculated using triple smoothing of price and is essentially a trend-following tool. TRIX is a less known indicator but it has powerful signals when used correctly.
 

TRIX is a strong technical indicator which I personally use for trend trading.

Tip: From experience, the best way to trade the TRIX is by simply trading the signal line crossovers. Combine this with a top-down approach (viewing higher timeframe's first then using a smaller timeframe's signal to enter into the direction of the higher timeframe's trend), plotting simple trend lines and waiting for breakouts and you have a winning system at hand.
Some traders like to trade the TRIX by waiting for the Zero line crossover. This method works fine but I find that the Zero line crossovers happen when a good chunk of the trend has already passed. 

If you have any TRIX indicators or info you would like to share please do in this thread!