We didn't make it. We seriously believe we have a strong aplication: experienced people (developers), revenue model, an advanced demo, and already very very good reviews from other people.
I am sure now that YC looks at two things basically:
-a team larger enough to have at least 2 guys working full-time until Demo Day (we had only one)
-younger coders (20-28) at most. We are 29, 31 y.o.
If you don't have those two things, you probably didn't make it in this round, since it was more competitive, even if you had a demo and your solution was very interesting.
Needless to say, we will move forward faster than ever now.
Most of the negative things I got in life turned out to be positive later if I look backwards. I hope it's true with YC rejection too. :)