I think most who post systems here are living in a fantasy land:
http://www.moneytec.com/forums/showt...ght=pipscooper
Why don't the systems here backtest well? Because the systems posted here are almost universally losing systems. Who in their right mind would post a winning system here for free? You can't apply money management to a losing system and turn it into a winning system. If you are applying discretion to a losing system and making profits, kudos but you would do better to find a winning system and apply discretion to that. Many here don't backtest their systems or ideas (even self proclaimed expert system sellers). Many of those who do backtest use buggy software that makes the results seem rosier than reality and so they chase their tails or lose money trading a flawed system.
To have a profitable system takes work to develop, time and effort to test using sound assumptions, an understanding of the basic market forces and of an underlying principle that can be exploited.