You're talking about apples and oranges. Hardware and web apps are very different. Hardware still has lots of genuine inventions. Web apps--especially in the social space--all have the same kinda features at the end of the day.
So if you are a client and you come to me with an idea about a social network for plumbers that has an inbox feature, the max I might agree to is that I won't launch a similar product for his market...but I would be hesitant to even make that promise. I would never give away my right to have an inbox feature on a future venture, lol. Of course, you can totally make me agree that I will not reuse any code or specific modules I program for you will be yours.