What is Blurb?

Legal Definition
A blurb is a short promotional piece accompanying a creative work. It may be written by the author or publisher or quote praise from others. Blurbs were originally printed on the back or rear dust-jacket of a book, and are now found on DVD and video cases, web portals, and news websites. A blurb may introduce a newspaper or magazine feature story.
-- Wikipedia
Legal Definition
When a publisher has a summary written to reccomend a book. It is printed on the books dust jacket or in an ad.