https://charman-anderson.com/2010/06/22/how-new-fourwhere-maps-plotting-foursquare-yelp-and-gowalla-could-be-useful-for-journalists-journalism-co-uk-editors-blog/
How new Fourwhere maps plotting Foursquare, Yelp and Gowalla could be useful for journalists | Journalism.co.uk Editors' Blog