Facebook is a great example of "APIs are important" but the Facebook API for apps is completely different than anything they'd use for their pages. Especially

Facebook is a great example of "APIs are important" but the Facebook API for apps is completely different than anything they'd use for their pages. Especially back in the old days, when apps lived in a proxied sandbox and all of the params were passed into them, this code could not have been useful to the regular Facebook-only experience. So, I don't think Facebook really counts as an example that supports the author's argument.