Charles: I think the reason superscripts show up fine in your blog is because the line-height in the stylesheet controlling the look of your blog is set at 200% -- basically it is doubles-spaced. The code in your stylesheet template (it's just Movable Type's "Clean" style sheet for 2.6x) is:
font-family:palatino, georgia, verdana, arial, sans-serif;
Other blogs -- like mine -- have either smaller line-height percentages or just don't bother formatting the line-height, so it just defaults to the standards single-space look. Thus use of the superscript tag pushes things out of alignment.
And I just noticed some weird "hash" code thing on the bottom of the preview comment screen. It looks like there is something I must tend to. Frown.