Also "isn't as funny as it used to be". Used by long-time readers or viewers of a humorous magazine, comic book, or television show (extend this to any other medium you want) to describe the current state of that magazine/comic/show. Usually, IMO, the quality of the thing in question hasn't decreased -- rather, the person doing the criticism has just become used to that type of humour, so it no longer inspires the jaw-dropping hilarity it did when it was new.

Has been applied to Viz, Knights of the Dinner Table, and Mad Magazine to name just three.