Facebook is a walled garden. A closed network.
Facebook was built on top of the Internet and the World Wide Web, but limits building on top of it. This stifles innovation.
Wikipedia partially got its start by digitizing out of copyright articles from Encyclopedia Britannica. Facebook's first incarnation was as FaceMash, a site that was (possibly illegally) built around photos of students at Harvard University. This attests to the ability of small seeds to grow into something powerful. This sort of competitive building on top of the work of others should be encouraged by society.