Markets change constantly, so adjust your settings according to the market you are trading in. (bull/Bear/range)
High length number are more smooth, but gives less signals. Low length number will give more signals, but gives more whipsaw. This indicator can also be used to identify divergences.
If continue to be below center line means we are in strong bear market, if above means we are in strong bull market.
If constantly is in overbought/oversold area means there is strong momentum (up trend/down trend)
It is more accurate traded with market that moves sideways (range markets). (Common mistake) Just because, it is overbought/oversold does not mean it will reverse immediately. Always look for price confirmation when using , DO NOT MAKE DECISIONS SOLELY ON BASIS OF . It is wise to use it with other indicators. Failure Swings http://www.investopedia.com/articles/technical/03/042203.asp