Blurbs: Writing Previews of Web Pages
On the web, a blurb is a line or short paragraph (20-50 words) that evaluates (or at least summarizes) what the reader will find at the other end of a link. A good blurb should inform, not tease. Usability testing will help you determine the best way to lay out your blurbs, but this document will help you write the content.
http://www.uwec.edu/jerzdg/orr/handouts/TW/web/blurbs.htm