Online communities offer a lot of value for marketers. They often serve as a reference groups to consumers and influence their decision-making (De Valck, Van Bruggen and Wierenga 2009); they can be an important sources for marketing research (Kozinets 1999); they can be used to engage customers in collaborative product innovation (Sawhney, Verona and Prandelli 2005; Füller, Bartl and Mühlbacher 2006); and brand communities can be an important source of loyalty (Muniz and O’Guinn 2001; McAlexander, Schouten and Koenig 2002).