I think it needs a lot of work. The interface is nice but it's missing a lot of symptoms and rules. I think it is repeating expert system work that has probably already been done.
In it's final result it should make a mention of urgency in seeking healthcare and what to do in the meantime.
We'll be adding symptoms based on user input analysis and building out the symptom synonym engine.
True, there has been a lot of work in medical expert systems. DXPlain is an old one that tends to come up a lot in our conversations. We have several Hopkins medical informatics specialists advising us and I would say that our algorithm is novel.
Moreover, past attempts have attempted to codify a medical expert's knowledge (eg let's ask this smart doctor we know to determine disease prevalence). We calculated it from clinical data and can continue to learn as more people use it.
In it's final result it should make a mention of urgency in seeking healthcare and what to do in the meantime.