To hear something through the grapevine is to learn about something. It can also simply refer to an overheard conversation or anonymous sources of information, e.g. "I heard through the grapevine that Brad died."
Etymology
In his autobiographyUp From Slavery, Booker T. Washington says that slaves in the South kept up-to-date on current events by "what was termed the 'grape-vine' telegraph." However, the New York Public Library contends that the phrase derives from the infamous Grapevine Tavern in New York City's Greenwich Village. During the Civil War it "...was a popular hangout of Union officers and Confederate spies... It was the ideal place to get news and information, or in the case of spies and politicians, the ideal place to spread rumors and gossip, leading to the popular phrase 'heard it through the grapevine'." The term gained a boost in popularity through its use in the Motown song I Heard It Through the Grapevine, a major hit single for both Marvin Gaye and Gladys Knight & the Pips in the late 1960s. Grapevine communication existed from the American Civil War to the First World War. It was coined this because of its nature of networking and reaching several at once; it causes the transformation of information between one individual and another.
Features
Flexibility: There is no formal control over grapevine, so it is more flexible than other forms of communication. This also makes it more vulnerable and problematic, as one cannot send a message to any specific person, but is rather putting faith in the vagaries of luck, having no idea how many people, or who, might eventually hear the communication. Compare this to sending a letter to a person, or telephoning them, for example. Rapid communication: It is faster than many other forms of communication such as the postal service or posting bulletins. No record: There is no evidence which can be documented for future reference. Distortion: The message which is passed gets distorted when it passes from one person to another. Spontaneity: Grapevine communication is spontaneous as it is passed automatically from the top level of the organization to the bottom level without any difficulty in delivering the message. It is used by management to spread information that either cannot be shared officially or in an attempt to test the waters. Cheap: It does not require any funds to take place. However, it can cost the speaker money if there are negative consequences of messages being garbled in transmission from person to person, or if they fail to receive the message through some misunderstanding, such as others believing they were already informed, since there is no control over or record kept of the communication and thus no idea of who heard it, when they heard it, or even what they actually heard.
