Copyright
Makes a copyright message available which may or may not be displayed by a search engine. "This document copyright Use for non-profit and education purposes explicitly granted."
Again, this is the only information people looking at this entry in an index will have, so make sure the description, title, and key words all contribute to an useful summation of the content of the site the document leads into. (You can also define your own meta attributes for local indexing. More Meta Tags