I upgraded my WP blog to 2.3 (from 1.something!) this weekend, and I've been going through old posts and cleaning them up a bit.
When I hit the post for July 28, 2007, I saw that it broke the site's layout: instead of being main column > left sidebar > right sidebar, both sidebars wound up under the main column.
Weirder still, every post older than 7/28/07 suffers from the same problem. I can't see anything that they have in common, and I don't remember making any changes to my old install or design at the end of July.
What the heck is going on? Thanks in advance!