Ok, so I've seen this abbreviation lots of time and every time I ask what it means everyone says "I don't know". And what's even more surprising, the people who actually use IDK are the first to say "I don't know". :o
I've come to the point to believe EVERYONE in the world will reply "I don't know" whether they know what it means or not.
But I really, really, really want to know what it means. Do you known what "IDK" means? =P