What is copyright?
Simply, it is the right to reproduce a work. It can also refer to who has the right to display a work, to modify a work, or intellectual property.
Why do we need copyright?
"Congress shall have power…To promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries”
In other words, our Founding Fathers thought a limited period of exclusive use of one's work would promote innovation.
What works fall under copyright?
Multimedia (including web-based works)
Photographs and other images
Films and audiovisual works
… Basically, anything you might want to use