I'm the co-founder of The Tech Block http://thetechblock.com and we sort of built something similar to Medium (before Medium existed) except it's focused on Technology and we pick and choose the pieces that go on our site.
Though it has similarities, the big difference is that our site is not a place where you'd actually type out your article. Instead, if it's housed on your site already, you can choose to cross publish to our audience of tech enthusiasts.
Love the look. Two things: 1) The author info gets in the way on the left, making it harder to read (remember we reading in F), 2) Those outgoing links, I would rather have you guys grab the content and reformatted nicely within the site for a unified experience.
Though it has similarities, the big difference is that our site is not a place where you'd actually type out your article. Instead, if it's housed on your site already, you can choose to cross publish to our audience of tech enthusiasts.
If you haven't heard of it, give it a look.