A camera is an eye into the world, a portal for those who aren't satisfied with the eyes that they've had forever or for those who wish to share experiences and ideas with others through a very realistic visual art form.
Some cameras are very small (the Gameboy Camera, for instance). The very first ones were very large, requiring flash powder to operate and the big, funny curtains that you had to stand under.
Other cameras take moving pictures. They influence the content of movies, TV, and now the Internet through ever-increasing technologies and plain straight-shot photography like that which was used in the early days of cameras.
Use cameras for art, and share your life with the world!