Thanks!
That's an interesting question, and one that I've only started to address for myself quite recently.
This originally started out as a hobby project (I was a freelance web developer, but I'm now working as an IT Director at a startup I helped co-found a few years back, so I want to keep my web development active), but it's done better than I thought it would. I'm getting 3-5 submissions a day, and so I've decided to put more effort into it and figure out how to differentiate it from the likes of angel.co and other similar sites.
Angel.co, for example, is geared more towards raising funding from syndicate investors, and acting as a mini news outlet for that startup. Newborn, on the other hand, presents the startup, and gives enough information to allow the reader to decide whether or not they wish to visit their website, or download their app. Rather than trying to keep the reader on Newborn for as long as possible by having all the information there, I want to, in sense, hand over that reader to the startup, and allow them to finish the conversion process. It's their startup, after all!
So in essence, Newborn's added value is that is showcases startup at their early stages, gives the reader the information they need to make a decision (as to whether they'll find out more), and then let them do what they want.