An acronym for a phrase often used in short, connected communications, including email, SMS, forum postings, in-game chat, etc.
Pam: "I don't understand that webcronym - what does it mean"?
Bob: "What Do You Think?"
Pam: "IDK, that's why I'm asking you."
LOL, ROFL, HTH, YMMV, G2G, BRB, AFK, RTFM, WTF, FTW, FWIW, IDK, OMW, OMG