We've had open Web APIs. We've had OpenID. We've had ambitions for semantic web and microformats. We've had API mash-ups. All of this has been closed, abandoned, or morphed into a locked-in monetized hell when VCs demanded their money back.
†) it's symbolic of course, but that's when shutdown of Google Reader deflated enthusiasm about syndication. About that time Google dropped their "don't be evil" motto, and wrote a spec for launching secret DRM APIs from HTML5.