“A snowclone is a particular kind of cliche, popularly originated by Geoff Pullum. The name comes from Dr. Pullum’s much-maligned “If Eskimos have N words for snow, X surely have Y words for Z”. An easier example might be “X is the new Y.” The short definition of this neologism might be n. fill-in-the-blank headline. The phenomenon is real enough to have 90,000 Google hits as of this moment and a Wikipedia entry.
The definition of snowclone is somewhat fluid, by its nature, but there are some ground rules. I consider a high number of google hits with significant variation evidence for a phrase’s snowclonehood. Snowclones are a subset of cliches, but not all cliches are snowclones. (Depending how how strictly you define “cliche”, not all snowclones are cliches, either.) Your favorite Simpsons quote is not necessarily a snowclone.–The Snowclone Database