The index is just what the name implies in that it is like any other index that uses multiple currencies/securities in order to establish an average to create a value. It is measured against six other currencies. Click here to learn more. http://en.wikipedia.org/wiki/US_Dollar_Index
1. I use it to help guide my view on whether the USD is likely to to strengthen or weaken. I don’t trade it specifically (although there may be some ETF’s available).
2. Some chart providers provide a feed so you can view it. But it is an option that not all providers have.
3. I use the same technical analysis as I would on anything I trade.
4. This helps in trading against all pairs where the counter currency is the USD. Such as EUR/USD, GBP/USD, USD/CAD.
Cheers
'Market and Human' Psychology perspectives with tips on how to avoid common mistakes by 
