GIFs, Authorship, and Copyright

A reader pointed me to a blog entry over at the Library of Congress discussing animated gifs. The posting describes a little of the ubiquity of these Internet-spawned forms of communication and then asks the question: what about copyright? The answer seems to be that copyright claims don't arise because animated gifs rarely attribute authorship to their creator and because they often use tiny fragments of previously published media in a society where we generally understand the creative reuse of small samples to be fair use. RIAA excepted, of course.