In the November 5 Editor’s Draft of HTML5: A vocabulary and associated APIs for HTML and XHTML, there is a curious reference to the “sarcasm” tag.
18.104.22.168.7 The “in body” insertion mode
When the user agent is to apply the rules for the “in body” insertion mode, the user agent must handle the token as follows:
An end tag whose tag name is “sarcasm”
Take a deep breath, then act as described in the “any other end tag” entry below.
This is the only reference to the tag, so I guess only the closing </sarcasm> tag is allowed, not the opening <sarcasm> tag.
Perhaps this was a test to see if anyone’s actually reading?