I think your second tip is precisely what I've been trying with http://2FB.me because Shareable Tweets is kind of ambiguous. But for YouTubers who want to experience watching video as a simulcast, there is YouTube Share Enhancer which is the 2FB tool plus.

YouTube Share Enhancer: https://chrome.google.com/webstore/detail/youtube-share-enha...

SoundCloud Share Enhancer: https://chrome.google.com/webstore/detail/share-enhancer-for...