By the way, I've been wanting to make a prediction on your success, since I've been following your work with interest for a while: I think you will be successful, but not in the sense that YC or investors want from you. I just don't see you breaking out of the lifestyle-business loop. I believe that your technology will be your undoing - it will become so attractive to some outside entity that you will get swallowed up by them. I'm not sure if the technology - as-is - will be that valuable, but I'm assuming that you will iterate and adapt to the changing landscape. There is going to be demand for what you are creating - not for such trivial things as recommendations, but simply as data processing tools. There is going to be too much data, and the people who can structure it in whatever niche, will make good money.
The real question is this : will you guys be able to see the money when it comes? I, being an outsider, would not, but sometimes you can be so much of an insider that you don't see it either. You both seem pretty focused, and that's the big problem I see.
The final problem I see is this: you care about people liking you. I have the feeling pg likes you like he used to like sama. But the difference is that sama is ruthless and focused on making money - would you ever be able to? Can you bite the hand that fed you for the sake of the money?
Your recommendations system is small business and you will change it at some point. The new thing you build will be more interesting, I think.
That's my prediction! Let's see how many years I have to wait!