Kiefing bud is when you put all the bud on top of a silk screen (.80 micron I think, but different people prefer different grades), and you sieve it to collect all the crystals. Some cuntish dealers do this, keep the kief for themself (or sell it for an extortionate price - at least around here anyway) and then sell the bud. Sometimes it can be extremely difficult to tell if bud has been kiefed, as it still smells the same as unkiefed bud.