Microblogging is short messages that are delivered to consumers who have chosen to follow or subscribe to a given microblogging feed. The most popular microblogging service is Twitter, but other services such as Plurk, Tumblr, Identi.ca and Weibo are popular in other areas of the world. These services focus on consumers but can be used by retailers, as opposed to enterprise-centric microblogging sites (such as Yammer and Socialcast), which focus on collaboration in the enterprise.