Lurker

In Internet culture, a lurker is a person who reads discussions on a message board, newsgroup, chatroom, file sharing, social networking site, listening to people in VOIP calls such as Skype and Ventrilo or other interactive system, but rarely or never participates actively. Research indicates that "lurkers make up over 90% of online groups" (Nonnecke & Preece 2000). Lack of trust represents one of the reasons explaining lurking behavior (Ridings, Gefen & Arinze 2006).