The "honeycomb framework" defines how social media services focus on some or all of seven functional building blocks.  These building blocks help explain the engagement needs of the social media audience. For instance, LinkedIn users are thought to care mostly about identity, reputation, and relationships, whereas YouTube's primary features are sharing, conversations, groups, and reputation. Many companies build their own social "containers" that attempt to link the seven functional building blocks around their brands. These are private communities that engage people around a more narrow theme, as in around a particular brand, vocation or hobby, rather than social media containers such as Google+ , Facebook , and Twitter . PR departments face significant challenges in dealing with viral negative sentiment directed at organizations or individuals on social media platforms (dubbed "sentimentitis"), which may be a reaction to an announcement or event.  In a 2011 article,  Jan H. Kietzmann, Kristopher Hermkens, Ian P. McCarthy and Bruno S. Silvestre describe the honeycomb relationship as "present[ing] a framework that defines social media by using seven functional building blocks : identity, conversations, sharing, presence, relationships, reputation, and groups".