I. Findings that don't surprise me.
VC readers are disproportionately male, relatively to the internet average.
VC readers are disproportionately highly educated (people with graduate degrees).
II. Findings that do surprise me.
The relatively high percentage of Hispanic readers (25-30% more than the internet average).
The comparatively low percentage of white and Asian readers (below average in both cases).
The age profile of readers is older than I would have expected (age 45-54 is the best represented demographic).
III. Data that I wish Quantcast had, but doesn't.
It would be very interesting to know the ideological breakdown of the readership. Social science research shows that most people prefer to read commentary from viewpoints they agree with, and prefer to avoid that which comes from other parts of the political spectrum. That would predict that we have a mostly libertarian and fusionist/conservative readership. On the other hand, at least judging by the comments, the VC may have a larger proportion of liberal and leftist readers than most libertarian and conservative websites do. However, judging the overall readership by the commenters is a tricky business because commenters may be unrepresentative of the readership as a whole for a wide variety of reasons. For example, people who disagree with a post may be more likely to comment on it than those who agree.
It would be helpful to have the absolute numbers for many of Quantcast's categories, rather than just percentages relative to the "average" website.