It was a success in the sense that we learned a lot. If anyone wants to know about that, a lot of it is in the explanations here:
https://hn.algolia.com/?dateRange=all&page=0&prefix=false&so...
https://hn.algolia.com/?sort=byDate&dateRange=all&type=comme...
Some good threads to start with might be https://news.ycombinator.com/item?id=21607844 and https://news.ycombinator.com/item?id=22902490.
These explanations have become pretty stable by now—stable enough that I repeat myself incessantly: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...
*Edit: here's where we called it off: https://news.ycombinator.com/item?id=13131251
What that tells me is that the forces creating the HN front page don't have much to do with changes in the userbase over time. That's interesting, and I think to most people (me included, and pg probably included) counterintuitive.
After all, if you changed HN into a My Little Pony discussion site you'd lose 98% of old users, retaining the 2% who like ponies - and thereafter, 100% of remaining old users would like ponies.