Common affectionate name for KarlMarx by Marxist and post- (as opposed to anti-) Marxist thinkers and theoreticians. Uncle Charlie can be a bad-tempered, ornery son of a gun with some views that are nowadays considered hopelessly out of date, politically incorrect or just plain wrong, but he still retains the power to surprise you with unexpectedly useful or contemporary insights like GeneralIntellect.
Coincidentally, "Charlie" was also the nickname given to the Viet Cong by American soldiers during the VietnamWar. That name doesn't derive from any reference to KarlMarx, instead it is a shortened form of "Victor Charlie", which is how "VC" was in pronounced in the well-known PhoneticAlphabet used by (among many others) the US military.
Note that UncleCharlie and UncleSam often fight over gas money.