The NYTimes has an interesting article concerning bloggers excerpting portions of other news articles online.
The editors of many Web sites, including ones operated by the Times Company, post excerpts from competitors’ content from time to time. At what point does excerpting from an article become illegal copying? Courts have not provided much of an answer.
Brian Stelter, "Copyright Holders Challenge Sites that Excerpt," 3/1/09 New York Times, Business - Media and Advertising.