If I might expand the question to be about technologies in general, I'll submit OpenSocial[1] and Widgets[2] as two things I thought would be widely adopted, bu

If I might expand the question to be about technologies in general, I'll submit OpenSocial[1] and Widgets[2] as two things I thought would be widely adopted, but ultimately weren't. [1]: https://en.wikipedia.org/wiki/OpenSocial https://en.wikipedia.org/wiki/OpenSocial [2]: http://w3c.github.io/packaged-webapps/api/Overview.html http://w3c.github.io/packaged-webapps/api/Overview.html