This indicator is very old one.
It came from Metatrader 3.
I have no idea who coded it first for MT3. May be Nick Beluck.
Later on Ramdass (russian coder) converted it to MetaTrader 4. And later on many people created many variations of this old well-known indicator:
iTrend_indicator.jpg
Usually this indicator is using as a filter in EAs. For the first time we used it in Brainwashing EAs
http://www.forex-tsd.com/brain-systems/ and EAs are profitable for same pairs/timeframe during the 2 and half a year forward testing with same settings (coder: Nick Beluck).
Value of this indicator is fully depends on broker's data. It means: different value for different broker. Usually people are using some formula to averaging this value for same period of bars and using the value of the indicator for the broker they want to trade with. Otherwise it will be very different performance.
Later on many people created many other EAs (Terminator and so on) but this EA used as a filter only with any EA coded.
May be there is some EA which is using this indicator as a main one but I did not see sorry.
Just for information.