The definition is beautifully simple. I think that applications COULD be intelligent, they certainly gain data naturally, however could this be considered knowledge? Knowledge is an acquaintance with facts, truths, or principles, as from study or investigation. Can current AI study or investigate a principle, truth or fact? A social network could be seem to gain knowledge of a user's topical preference, however a social network does not naturally learn new skills. It is given new skills by a developer. Though I certainly don't think that AI is a myth, I think that with current technology it is probably out of our reach (for now).