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viewly is pretty new although it's been in the works for quite a while, I'm wondering why a update isn't just patched in for it.

A big question for me as well, since it cannot be simply 3rd party content not enabled through iframes because of security, since then YouTube and Soundcloud would also need to be disabled.

they are probably whitelisted and integrated. It's a matter of web-design back end probably the Steemit Inc. team has the site :)