Far be it from me to question Fred Wilson, but I actually believe he is not referring to an API, but is referring clean URLs. The reason I think this is becaus

Far be it from me to question Fred Wilson, but I actually believe he is not referring to an API, but is referring clean URLs. The reason I think this is because the second half (of the two sentences) on the RESTful section says "...every resource on your site needs to have a URL and ones that people can understand". Additionally, there is another section for APIs called "programmable". Seems like a minor misnomer, but still a good point.