You are probably thinking of a "tagline," it is not a quotation.
Here are some examples of it:
Quotations are for people who are not saying things worth quoting
Quotations are for people who don't say things themselves worth quoting
Quotations are for people who never say things worth quoting
"Quotations are for people who can't think for themselves."
- Joe Duong (well, okay, maybe this one's a quote, but I've never heard of Joe Duong)
"Famous quotations are for people who have nothing of their own to say,
so be sure to use a lot of them."
-The Onion: Pisces