27.

“The architecture of Linux, the Internet, and the World Wide Web are such that users pursuing their own “selfish” interests build collective value as an automatic byproduct …

These projects can be seen to have a natural architecture of participation. But as Amazon demonstrates, by consistent effort (as well as economic incentives such as the Associates program), it is possible to overlay such an architecture on a system that would not normally seem to possess it.”

–Tim O’Reilly