What would be the effect on the effectiveness of a strategy or EA if you share it?

[chrisbenjy]

Basically, how would releasing a strategy or EA to a mass audience or a small community affect the profitability and effectiveness of the system?

 

In a small market, I would say if lots of people are using your system and are buying/selling at the same time as each other then you have greater power to shift momentum and drive the product. But forex is a huge market, so even if several institutions were trading your system it would have little or no effect on driving currencies.

 

If thousands, maybe millions of people were using the system. Could brokers or institutions use the system to show popular stop loss locations and "hunt" for stop losses to reduce the effectiveness of it?

 

What other effects are there?

 

I'm not keeping an EA or strategy private or anything, I'm just curious.