You Don't Know Jack Shit would be my expansion, but it's possible they meant something like You Don't Know Jacks (perhaps more than one person named Jack in the household?), You Don't Know Jack's (Jack's what?), or some reference to the computer trivia game You Don't Know Jack.
It's also possible I'm completely way off in left field, but "YDK" instantly parsed to me as "You Don't Know".
I knew someone who had "OMGWTF" on her plate. Still cracks me up they never caught it. Oh my god what the fuck? is just about the funniest I've heard anyone get away with. ;)
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Date: Nov. 25th, 2007 01:02 am (UTC)From:no subject
Date: Nov. 25th, 2007 01:26 am (UTC)From:It's also possible I'm completely way off in left field, but "YDK" instantly parsed to me as "You Don't Know".
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Date: Nov. 25th, 2007 02:32 am (UTC)From:no subject
Date: Nov. 30th, 2007 01:58 am (UTC)From:no subject
Date: Nov. 30th, 2007 01:59 am (UTC)From:no subject
Date: Dec. 2nd, 2007 02:50 am (UTC)From:no subject
Date: Dec. 2nd, 2007 03:05 am (UTC)From: