Updated

By Simon Evans

MIAMI (Reuters) - The yell 'Who Dat?' has become a greeting and rallying call for Super Bowl-bound New Orleans Saints fans but the NFL is clamping down on unofficial merchandisers who use the slogan.

The Saints have earned a spot in next week's Super Bowl against the Indianapolis Colts and last week's NFC Championship win over the Minnesota Vikings resulted in a whole range of official and unofficial products hitting the streets of the 'Big Easy'.

A league spokesman told Reuters they had sent cease and desist letters to six traders in recent days.

"It is very narrow enforcement of people infringing on Saints rights," said the spokesman who added the NFL's aim was only to stop products that appear to be official team items.

"If it is a non-football related product then it is a different story."

The orders have received criticism in local media in New Orleans where the 'Who Dat?' phrase goes back long before the formation of the Saints franchise in 1967.

'Who Dat?' now refers to a chant in local dialect "Who Dat Say Dey Gonna Beat Dem Saints?" and fans count themselves members of the 'Who Dat Nation'.

But some accounts chart the original use of the phrase back to Vaudeville shows over a century ago.

"Who Dat? belongs to the ages," wrote Peter Finney in the New Orleans Times-Picayune.

UNPRECEDENTED SALES

Trader Lauren Thom, owner of Fleurty Girl, a tee-shirt website and store, was one of those who received a letter from the NFL but after initially being "frightened" by the legal tone of the mail, said she had enjoyed unprecedented publicity and sales.

"It's been the best thing that's happened for my business. It has brought us a ton of traffic," she said by phone from her small shop in Uptown New Orleans.

Thom, a mother of three who lives behind her shop, said since the cease and desist letters that her store had been packed with customers buying other products out of solidarity.

But to add to the mix, a New Orleans firm Who Dat Inc, claim they, and not the Saints, own the phrase.

Who Dat Inc is co-owned by Steve Monistere who recorded a Who Dat? song with musician Aaron Neville and some Saints players in 1983.

Thom's website now features only a Who D@ tee-shirt with no suggestion of a sporting usage but when it comes to music, any attempt to control the phrase looks doomed.

Scores of Who Dat? songs have been uploaded to the internet since Sunday's victory.

K.Gates, whose Black and Gold (Who Dat?) rap has been one of the most popular, said his song has been downloaded about 30,000 times through online music stores.

(Editing by Tony Jimenez. To query or comment on this story email sportsfeedback@thomsonreuters.com)