- Average height for American women, 5'4"
- Average height for American men, 5'9"
- The height of Robert Wadlow, the tallest man who ever lived, 8'10"
Things are so askew in SL that avatars of RL average height or even taller get accused of being child avatars. Maybe this sort of display would help were it more common.
(No discussion of scale and height in Second Life should be without a reference to Penny Patton's "A Matter of Scale". If you've not read it, I hope you will.)