What Is a Talent Community in 2013?

In 2013, it seems everyone is talking about talent communities. Some people call their job alert system a talent community; some people refer to their CRM as a talent community; some people call their LinkedIn company group a talent community; and some job boards refer to their resume database as a talent community. And, it seems, there is a vendor solution for each flavor of talent community. These diverse opinions create interesting discussions and debate until it is time to seriously consider whether to invest in a community of talent; then the confusion sets in and creates the question — what is a talent community?