This article describes how today, social media enable users to comment on brands in a multitude of ways. Although it is undoubted that this can have a substantial influence on the way brands impact on consumers, comparatively little is known about what motivates consumers to recommend brands in social media and whether there are cultural differences therein. This article aims to determine the factors leading to either positive or negative communication about brands on Facebook, YouTube, Twitter, and brand-related blogs based on a representative sample from Germany and the US, each with 1,000 adults. Complementary to an analysis of factors determining a general inclination to recommend, a principal component analysis of the diverse motives to do so exhibits patterns being largely consistent in a cross-cultural perspective, however, with differences in specific practices concerning gender, age, and formal education. A cluster analysis as well as taking a look at “influencers” provide a basis for developing differentiated strategies of brand communication and management respectively.