Stack Overflow Is A Marvel of Useability

I have been aware of Stack Overflow for some months, and have looked briefly at it once or twice. But this week I had the first occasion to post my own question, so I spent more time and much more focused time than ever before. The core concepts for Stack Overflow are terrific. But the many terrific useability touches just seal the deal. This is the best useability experience I have had in a long, long time. Some things that stand out, in no particular order:

• The insta-preview is perfect.
• Smart parsing of my offline-edited, pasted-in question was very impressive (converted *word* into italics, converted"-" into bullet).
• Everything is BIG and easy-to-read (Atwood must be following his own advice about Fitt's Law)
• The suggest-answers-before-submit was: 1) Painless, unlike the typical step-by-step, HTML-round-trip approach; 2) Pretty accurate (though ultimately did not answer or change my question).
• The auto-complete for tags is very well-done.

So I would say that Jeff Atwood is doing a good job eating his own dogfood when he says "relentlessly polishing and improving every little part of it -- no matter how trivial -- you're not executing".