Fibonacci extension levels are a great tool. It works on every time frame, both short and long term. Look at daily chart of eurusd. Falls started in August, later we had strong correction move up to 0.78, since then we have strong falls (if you want to read more about trading corrections, read my article titled What is Fibonacci retracemened?). They stopped first for a minute at 118% extension but bears were back and eurusd kept on falling.
Until now. When you look closely at eurusd chart, you can see that current strong bounce back started at 138% extension. EXACTLY AT THIS LEVEL. Remember, falls started in August, and we have now end of January 2012. Still, it is almost exactly level where falls stopped (for now).
How can you not love (use) Fibonacci trading?