Ok, now everyone's comment avg is visible in their profile.
http://news.ycombinator.com/item?id=1741408
http://news.ycombinator.com/item?id=1485254
http://news.ycombinator.com/item?id=1349459
http://news.ycombinator.com/item?id=1349455
Those are all comments by me that were helpful to the parent, but which are "punished" by the public display of avg.
If you want it scaled to fit a continuum of "bigger is always implicitly better", a more reasonable number would be: average of (comment points/parent points)
Even if a number has no [absolute cardinal, > x] meaning, there is still a nominal information value to the datum.