A catch phrase is a phrase or expression that is popularized, usually through repeated use, by a real person or fictional character. They are especially common among TV and cartoon characters.
Today, catch phrases are frequently seen as an important part of marketing a character, with the phrase appearing on t-shirts and other promotional materials for the character's respective show or film.
Catch phrases attributed to real people are often based on something that the person would be expected to say, as opposed to something they actually did. These are also known as misquotations.
However, in order to be a catch phrase, a quote generally has to be more than a famous (or infamous) statement. It also usually serves two additional functions: first, to identify the speaker; and secondly, to serve primarily as that character's "trademark." A catchphrase can also identify something other than an individual character: Budweiser's "Wazzup" identifies the brand more than it identifies the individuals in the advertisement who actually say it.
A catch phrase is not to be confused with an infectious remark that enters the mainstream and becomes popular independent of its character. For instance, Zero Wing's All Your Base Are Belong To Us has some currency as a successful Internet meme, but is not a catch phrase because it does not serve as such a trademark.
Context is essential to many catch phrases. Although in the list of catch phrases, few people would recognise "No problem", "There you go" or "Yes" as catchphrases in themselves. For example, Marv Albert's "Yes!" is a catchphrase mainly due to his distinctive sounding of that word, and people who imitate or parody it try to duplicate his style. Similarly, when referring to tricky Anglo-German relations, the phrase "Don't mention the war!" evokes Basil Fawlty, especially when delivered through clenched teeth. But when referring to another war it may not function as a catchphrase at all.
- Livejournal's Catch Phrase Community (http://www.livejournal.com/community/catchphrases/)