Not ideas, per se, but intellectual work - inventions, software, business practices, fiction, you name it - that benefits many people. These benefits can be shared for free, so it's best for society if they are. People who produce these benefits should be rewarded, provided a means to continue their work, and given the incentive to create. The solution seems pretty obvious.
Except where otherwise noted, content on this site is licensed under a Creative Commons Attribution 3.0 Unported License.