Came to say exactly this. The chart seems to start (by default anyway) at the beginning of 2007. I'm guessing the user-base and thus activity of HN has increased considerably since then. So yes it would be good to be able to re-normalise in some way. By the number of registered users would probably be the simplest. By number of comments posted would be another, by number of submissions or even number of words would all be interesting.
Btw - my suggestions got me thinking - I assumed this is looking at posts and comments. Whether just submission titles or if includes comments will affect best way to normalise.
Btw - my suggestions got me thinking - I assumed this is looking at posts and comments. Whether just submission titles or if includes comments will affect best way to normalise.