Nike's Chalkbot Checks Into Tour de France

Nike's cancer-fighting chalkbot collaboration with Lance Armstrong's Livestrong foundation is hitting the road again this summer at the Tour de France, writing messages submitted by the public via tweets in partnership with Gowalla. Chalkbot, which prints on the pavement in water-soluble paint, recently won the Titanium Integrated Grand Prix at the Cannes advertising festival.

Users can tweet 40-character "messages of hope and inspiration" (such as this) to @chalkbot with the best printed on the cyclists' route — something Armstrong himself may need in light of yesterday's disappointing performance. Gowalla is also giving out Livestrong items to its members who check in at Nike retailers during the tour.

Separately, Gowalla is supporting the Threadless Everywhere Tour across America this summer, marking the 10th anniversary of the crowdsourced t-shirt site. Its mobile Airstream is also serving as a mobile Gowalla spot, using GPS to auto-update its location on the social check-in site. Anyone checking in on the Airbus will receive a limited edition Gowallazilla t-shirt from Threadless.