11.   In that campaign, the groups were depicted as buses filled with passengers all interested in a single topic like pets or fishing or music.

12.   Just volumes of messages, stitched together to discuss a single topic.

13.   News groups are wonderfully strange meeting places devoted to a single topic.

14.   Seldom in the image-driven, sound-bite campaigns of recent years has a single topic received such extensive exposure at the height of a presidential campaign.

15.   Some are sites that specialize in a single topic.

16.   The format has been rearranged, with the entire second hour dedicated to a single topic.

17.   The Net became a single chat room with a single topic.

18.   The service recently expanded its classical-music coverage from a single topic that encompassed everything to a board divided into a dozen subjects.

19.   The seven justices must determine if the amendments are clear, easy to understand and address only a single topic.

20.   The second hour of each two-hour program will henceforth be devoted to a single topic or personality.