I've decided I'm going to circumvent the historical debate over (mis)usage of the word "drabble" and invent the word "scrabble" to mean short purposeless scribbling of no particular length, because the available alternatives don't quite work for me. "Comment fic" and even "crack fic" more or less imply coherent form, a beginning and an end, and "snippet" suggests that it's part of a larger whole, and that more is coming. (Ha ha ha!) From what I can tell there's really no fannish word for "a jotted bit of crackheaded drivel that will never become anything more than what it is." And I think we need that word.