• by Sarah Mahoney  @mahoney_sarah, March 10, 2010

First, an update from the fun-loving shamrock crowd: The NRF survey, conducted by BIGResearch and based on responses from nearly 8,600 adults, reports that 80% of Americans declare themselves Irish on March 17 by wearing something green. And 29.6% actually celebrate, either by attending a party or hitting a pub.

But this year, the interest has shifted a little: 18.9% will go to a private party, compared with 16.7% in 2009, and 23.3% will decorate their home or office, versus 21.8% last year.) As with most holidays involving tinted beer, young adults are most observant, with 39.2% of them (18 to 24) planning to attend a private party, up from 35.4% last year. These younger partiers will spend even more: $40.18 this year, up from $36.05 last year.

Now for the Denny's downer: The fast-food restaurant stepped in it big-time when it released an ad linking an all-you-can-eat French fry promotion to the Irish Potato Famine. (And no, you won't find the spot anywhere. It has vanished, like a million or so Irish people in the late 1840s.)

And while the seriously Irish tend to be very good-natured about the way Americans glom on to all-thing-leprechaun, the ad sparked a Facebook backlash: "Denny's Boycott -- the Irish Demand Respect" page has 1,400 fans, and bloggers have also been shaking their shillelaghs at the restaurant chain's gaffe. (Irish history buffs will delight in the use of the word "boycott," which originated in Ireland in 1880, when ticked-off townsfolk got so fed up with British landowner Capt. Charles Boycott that they refused to speak to him, serve him, or even deliver his mail.)

Denny's gave Marketing Daily this statement: "Denny's has a history of using humor in its television advertising. It is certainly not the intention of the company to offend anyone or any group, and we apologize if this spot has in any way. As a result of the feedback we have received from our customers, the spot is no longer on the air."

Denny's is continuing its "Endless Pancakes and Fries" promotion, however, which started in February and runs through the end of March.