Starting in January Yahoo’s search results pages will feature shorter ad descriptions, which Yahoo predicts will increase clicks and conversions.
Currently each sponsored listing that appears on the right hand column can contain up to 2 lines for the title, 3 lines for the description and 1 line for the URL link. With each ad taking 6 possible lines, Yahoo will be able to include more ads per page by reducing the size of all ads. This benefits advertisers who will have a better chance of appearing above the fold now that more slots will be available.
See the full text of the letter sent to Yahoo Search advertisers explaining the new display strategy here.