As Unitarian Universalism is a creedless religion and one that has traditionally been focused on good works, the deeds and accomplishments of Unitarians, Universalists and Unitarian Universalists generally speak louder, and are more well known, than our words or our discussions of theology. It may be easier to understand UUism as a living faith by noting the individuals who have been associated with the denomination.
In American history, the first well known Unitarians were John and Abigail Adams, Ben Franklin and Thomas Jefferson. On the Universalist side there was Clara Barton and Susan B. Anthony. Many of the transcendentalists, such as Ralph Waldo Emerson, Henry David Thoreau and Louisa May Alcott were among those who are counted as UUs. Contemporary Unitarian Universalists include Sylvia Plath, Pete Seeger, Christopher Reeves and Paul Newman.
A perusal of the website Famous UUs is quite revealing.