I just added last edit info to the Bitcoin theme. Hover your cursor over the post time.
Edits aren't recorded when they occur within 5 minutes of the post time. (This has always been the case.)
Excellent excellent excellent. This is very useful. For anyone that can't see the difference, what is shown is a dotted underline under the post time if there has been an edit. When you hover over it, it changes the cursor to a question mark pointer and shows you the last edited time.
Thanks again, theymos. Great way of implementing this feature unobtrusively.