Web hosting company 123-reg has launched a promotional campaign that combines social media interaction and out-of-home adverts, using 160 'streetliner' advertisements installed on 160 buses throughout Greater London during the Olympics period.

The project sees 123-reg's fans invited to guess the location of a bus as part of weekly picture contests on Facebook and Twitter, and to submit bus-related stories.

"As a primarily online company, we felt it was worthwhile to move our advertising 'offline' in order to gain traction, and we look forward to measuring the results," says Thomas Vollrath, chief executive, 123-reg.