There is a meaningful subset of HN'ers who have fairly direct access to PG and the other YC partners - the current class and alumni of Y-Combinator. For the rest of us, PG's essays cover a lot of his background as does his book Hackers and Painters.

The format of Ask PG seems to work pretty well. A mix of technical questions regarding YC applications, changes to HN, and interesting business questions tend to get deeper answers than is common within the limits of AMA.