You didn't hear of it before? It has been all over SteemIt this last month. This is my 4th post about it, that's how good I think the concept is.
First you connect your Twitter, Instagram and/or YouTube account from within the Share2Steem website.
Then, whenever you want a post you make on one of those sites to appear on your SteemIt blog, you just add the hashtag #share2steem to it.
Posts without that hashtag aren't shared on the Steem blockchain, so you can be selective.
Posted using Partiko Android
Interesting concept for sure.