Note: this forum is about the discussion of theory, not the actual practice of law. For actual legal advice, call a lawyer.
There's two types of patents we commonly see: products (i.e. the driver in a speaker) and business methods. Business methods patents are much newer and tend to be the contended ones -- one click checkout, online auctions, etc. But even as broad as they are, it's not about an idea so much as a specific process for a business application.
To be patentable an invention must be useful, novel and not in the obvious path. That is to say you need to make something new that wasn't the logical next step. With so many patents being filled many that seem to fall short of that guideline have made it in but having a patent does not do anything on its own -- you have to enforce it to benefit from it and doing so risks it being challenged. Patents are not cheap to file (talking tens of thousands of dollars) and far more money to defend and enforce over time.