This seems to be basically just a chat server (with message attachments). The notebook style UI is cute but doesn't seem to mean anything. Is there anything here I couldn't do on Skype?
What platforms does this support? There's a picture of a laptop, a tablet, and a phone. They all look vaguely like Apple products, so maybe this is Mac/iOS only, or maybe that's just the icons you happened to have on hand. If it is Apple only, that kind of platform limitation will be a big (almost certainly fatal) handicap to collaboration software. If it isn't, you need to make that clearer.
A hamburger menu (traditionally used to mean "everything else") on the left, and an ellipsis menu (also traditionally used to mean "everything else") on the right? Oh dear.