Most people now are familiar with Foursquare, the location based social network that allows users to 'unlock' their city. The more you use it the more you get out of it, allowing you to see where your friends have been and what they and others think of the places they have visited. The more you visit places the more you are rewarded, with the person who is the most frequent visitor to a place becoming its 'mayor'.

Shelter Scotland has shown that is keen to move with the times and is the first charity to use Foursquare in its new digital media campaign. Smartphone users who check in on their first visit will be able to get a three for two deal on their purchases and as a reward for their loyalty the deal is repeated every six check ins. Visitors will also be able to collect eight limited-edition badges designed by Stina Jones, one at each of the eight shops. The first ten people to collect all eight badges will get an original print by the designer.

At the moment the campaign is being tested in Shelter's eight Edinburgh shops. However if it is a success the charity hopes to role it out across the rest of its shops in Scotland and then extend nationwide in 2012.

Watch the charming hand drawn animation a the top of this post for further details of how it works.