The creative campaign, which includes TV, radio, print and digital executions, launched Tuesday.

The speaking avatars were developed by Oddcast, a New York-based media technology company that develops conversational character products, which earlier this year produced the extremely successful "Monk-e-mail" campaign for Careerbuilder.com.

Oddcast has developed more than 100 avatar-based viral campaigns. "They're a great way to reach out to target constituents and drive awareness," says Adi Sideman, CEO of Oddcast. "E-mail recipients are 60 to 65% more likely to open an e-mail from a friend rather than a brand and 30-35% more likely to pass that e-mail along to another person."

In 2006, Oddcast deployed more than 40 avatar-based viral campaigns, which involved 35 million unique characters and which resulted in 19 million e-mails being sent, opened and passed along, the company says.

"These statistics lend credibility to these types of campaigns and show that user-generated content and giving a target customer the ability to express him/herself is such an important aspect of marketing and media strategy these days," says Sideman.

McDonald's national grassroots and viral campaign will last for four weeks and includes the launch of mysnacktime.com and a viral campaign that can be accessed at the bottom of that URL.

Visitors can answer a series of quirky questions and send an e-mail to friends, who will see and hear a cartoon character in an office cubicle, apparently addressing them. All the possible scenarios center on inviting friends to join in on "Snack Time" at McD's.

In addition, the company sent "Snack Teams" into the streets of New York, Los Angeles, San Francisco, Chicago and Miami on Tuesday to hand out "Arch Cards" for a free Chipotle BBQ Snack Wrap. The teams also signed up consumers to receive their own invite to "Snack Time."

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