NEW YORK — A phone message to the nation: Please call 510-872-7326; Marc Horowitz wants to meet you for dinner.

Go ahead — dial it. If he doesn't answer, just leave him a message. That's what thousands of people have done after seeing his number on a dry-erase board in a Crate & Barrel catalog photo last fall.

Horowitz, a conceptual artist in San Francisco, was working as a photo assistant on a catalog shoot when he came up with an idea for an art project that would question social barriers.

The dry-erase board looked too blank, so he decided to write his cellphone number on it — and maybe take a road trip to meet anyone who called.

"It's about illuminating the importance of conversation between strangers," Horowitz said. "We just plug into our computers and think that's the way to live, but old-fashioned face to face is what it's about."

It's not his first madcap art project aimed at bringing people together. Last year, he ran errands with strangers, which consisted of selecting cereal and folding laundry. The 28-year-old also regularly hands out free coffee to passers-by in a San Francisco park.

The dinner tour was supposed to be a three-month journey to meet a few dozen people, but now it has ballooned to include thousands. Horowitz left last week and plans to gone at least a year.

But exactly who calls a number they see in a photo on the page of a Crate & Barrel catalog?

Gregg Piazzi, a 36-year-old chef who lives in Columbus, Ohio, was caller No. 34. He saw the number while flipping through the catalog and noticed it was not one of those fake 555 numbers.

"There's a real phone number in here," he said as he dialed. "I gotta call."

Horowitz answered, they talked for a few minutes, and now dinner with Piazzi is a planned stop on the nationwide tour.

Horowitz did receive the occasional angry rant, and at least one offer for sex. Some callers talked about how they were raised by nuns, work at a gas station or take several kinds of medication.

"A lot of people are lonely and they just want to talk to somebody," Horowitz said. "I think it's just curiosity and about people wanting to reach out and connect with somebody."

Horowitz eventually added his e-mail address and Web site to his voicemail greeting. After some publicity, his inbox was jammed with e-mails — dinner invitations, random ramblings and flirtations — from New Hampshire grandmothers to Florida firefighters.

They beg him to visit their homes and towns, offering "a mean lasagna" in Georgia, a "place to crash" in Massachusetts, "something like chicken and dumplings" in Alabama, coffee in Wisconsin and Shabbat dinner in Maryland.

In their e-mails, they share intimate details. One woman in Las Vegas is saving up for gastric bypass surgery and another in Texas is going through a "divorce from hell."

"It is because of people like you that I have a renewed hope in mankind," one woman declared in a 6:25 a.m. note.

"Congratulations for giving us something to talk about outside of the election, terrorism and Paris Hilton," another wrote from Pennsylvania last fall.

Horowitz sold his truck, bought a mini-RV, sublet his apartment and held a garage sale to help fund his journey. He has rejected offers to turn his adventure into a TV show or documentary, which he believes would poison the purity of the conversations he hopes to have. But, he allows, he might write a book.

Some people would rather not eat dinner with their own families, much less strangers lonely enough to dial a random number. What was Horowitz thinking?

"It's about really listening and knowing that everybody has something important to say," he says. "This is real conversation with real people — it's something you can't buy."