You know people with common mental illnesses are just normal people, right?
It doesn't look targeted at anyone in particular. Doesn't help that the text on the page doesn't make it clear either. The hacker news headline says "unusual people", the landing page headers says "atypical people", the first bullet point says "you can chat about whatever you want" (so does every other social network ever). I admit if I read more closely further down, it would be clearer it was more social anxiety and mental illness targeted, but I had made a judgement about as fast as 95%+ of other random users would when reaching the website.
Besides that, something _original_ or eye catching might be worth it. But that's something that requires excellent execution.
This landing page looks to me as if it's trying to attract the most mainstream audience possible, like trying to be Facebook or ChristianMingle or something. It doesn't have to look too crazy, but it should look different from the norm, at least in colors or themes or something. Try looking at some unconventional sites and see how they sell themselves.