The term "bluebird" has multiple meanings depending on its context.
1) In a general sense, it refers to any member of the family of birds known as the Thrushes or Turdidae which includes several species such as the Eastern Bluebird and Mountain Bluebird among others. These are small, colorful birds with blue feathers on their wings and tail.
2) The term can also refer to a type of mailbox specifically designed for rural delivery in the United States. It is called "bluebird" because it resembles an old-fashioned wooden birdhouse.
3) In popular culture, "bluebirding" refers to the practice of using a computer program or algorithm to automatically post comments on social media platforms with the aim of promoting a particular agenda or political viewpoint. This term is derived from the idea that these posts are like "bluebirds of happiness," bringing joy and positivity to those who see them.