do we really need a new format in this space? either you can express yourself in less than 141 characters therefore you can tweet and if not, write blog post.
I guess that the point is that you can share multiple items and connect them with you own narrative, a bit like a mix tape or collage for the digital age. So it is different to both.
As Sysky said, edgee is not a medium length text post (did you even click on the link?). It is a new concept, a new format altogether where you can link and connect different media items with your own thoughts. We want to lower the barrier to entry for people. You can request an invite on edgee.com and try it out yourself