80% of HN is using Chrome? That is unexpected. I'd figure if Firefox would be popular anywhere, it would be here where I would imagine most people run the aurora builds (at least, I do).
The number has been mentioned to be wrong, and it is. I have Aurora 17.0a2 on Ubuntu 64 bit, which is 9 days old.
The OS numbers also seem off, saying 54% of HN is browsing from OSX but 0% from any Linux?
The facebook numbers seem strange. 45% are using Safari but 75% are using Windows. I really don't think 20% of those page views are from Windows users running Safari.