If you have something that works and share it with the world, you'll quickly find yourself with 1000 competitors. They'll probably be poor competitors, but because of the nature of SEO, they just might outrank you for no good reason at all.

Or the competition might bid up (at their loss, but yours too) whatever you need as inputs (like traffic sources).

Many believe that ideas are worthless, but I don't. Especially on a business/startup forum. I really don't want the competition.