In my vast experience some markets seem to adhere to the pivots lines more than others. I've found the Cac and S&P to be quite good. Helen has posted lots on the EuroStoxx I believe she's mentioned it sticks to pivots well. As regards a sysem:
Again Helen mentioned this site http://220.127.116.11/spreads/ that mentions using S/R lines a way of taking advantage of spread betting bias. Basically as it approaches a line bet the other way and hopefully enjoy the spread switching back in your favour as the price bounces off this line. Predicting when it will bounce off or break through seems to be the key. I've been experimenting different indicators, but found nothing too reliable yet. Fibonacci lines could also be used in conjuction as discussed on another thread. http://www.trade2win.co.uk/boards/showthread.php?s=&threadid=4205&highlight=pivot
They do seem to work on the STOXX, but will be breached often in strong trends or only provide a minute or so respite. Also they act on STOXX (and I can only speak for that as it's all I have used them for) within a 4/5 point band, so you can't be exact with them. Then again you can't with any other sort of S/R. My attitude is it's worth knowing where they are, lots of people use them so they are likely to be "sticky". Same things applies to yesterdays, H,L,C values. It's all additional info that can make a difference between profit and loss and you need all the edge you can get.