Wieden + Kennedy, Portland and Nike are continuing the last year’s Chalkbot campaign, which won Grand Prix Cyber Lion at Cannes International Advertising Festival 2010. The simple but lovely movement was started in support of Lance Armstrong’s Live Strong Foundation, which helps fight against cancer.

The idea of the project is that people from different countries come to Twitter (@chalkbot) (as well as other services like Facebook, WearYellow, etc.) and write “messages of hope and inspiration”, both personal and not, of 40 characters or less. The catchiest ones appear on the rout of the Tour de France (July 3-25), printed by a machine that sprays the text in yellow chalk all along the roads. When submitting the message, users also enter their name and e-mail, and in case it is printed, they get photos like these ones:

“The team has received tweets and messages from Doug Ulman, the Livestrong CEO, actors like Matthew McConaughey and Zack from Saved By The Bell, big time athletes like Larry Fitzgerald and Kevin Garnett, and even the voice of the Tour, Phil Liggett…and the quality of the messages we received this year has been amazing,” states the agency in the related post on its official page.