I recently discovered that we have a martin-gardner tag. Martin Gardner was a man who wrote about puzzles (of many different kinds), not a type of puzzle. What use is this tag? Does it tell people anything about the puzzle? He wrote about checkerboard, liars, chess, logic-puzzle, math, and many other types of puzzle, so certainly it doesn't narrow down the field very much! Who's going to decide "I want to filter puzzles that are of a type written about by Martin Gardner"? If they know anything about Martin Gardner, they'll probably already know about the kinds of puzzle he wrote about, so they can filter by liars or whatever.
EDIT: since the Martin Gardner tag tells us nothing about what kind of puzzle is concerned, it wouldn't work as the only tag on a question. That makes it a meta-tag and therefore (correct me if I'm wrong) ripe for burnination.