Accuracy is the best indicator of the typing quality. At equal speed, this is what best differentiates two typists.
This information is present only in the "Text Practice" mode (where the scores are anonymous) and in the "Top 1000" mode (which is a solitary mode where the scores are not visible to other users).
Yet it's in the normal / advanced and competitive modes that the display of the accuracy would have its very place.
Indeed, being beaten by faster than yourself does not necessarily mean "better" than yourself. There are sometimes very large difference in precision between very close scores.
This could be a great improvement for the site that I know is based on fun but should not neglect the quality for as much and even encourage its users to type with the minimum of wrong words at reasonable speeds rather than typing tons of typos at dizzying speeds.
Besides, I'm a relatively fast typist myself, but very inaccurate. And sometimes I feel guilty of beating someone who has a superior typing quality. ;)
So if we could see accuracy in the rankings of the 3 main modes as well as in the profile graph, it would be awesome. You could even give colors according to the degree of accuracy (red / orange / green) or a distinctive sign (tiny icon) to see at a glance whether the accuracy is low, medium or good.
As a reminder, the average accuracy is around 92%: