negative keyword list: A list that is made up of the keywords that an advertiser does not want their ads to show up for.

news aggregator : A software program that allows users to subscribe to and read RSS feeds.

non-targeted content : Generic text that isn’t customized for a Web site’s various subject themes and keywords.

null test : In A/B testing, a test that is run on two A pages (pages on which no changes have been made) in order to establish a baseline and make sure the traffic isn’t adversely affected.