Yahoo Inc plans to integrate Twitter into its collection of websites, as the company seeks to enhance the appeal of its online properties with popular social networking features. The partnership will allow web surfers to view the short, 140-character messages created by Twitter users, dubbed Tweets, directly within Yahoo sites as well as to publish their own Twitter messages without leaving Yahoo. The move, which Yahoo announced late on Tuesday, comes a couple of months after Yahoo announced a similar deal with Facebook, the world’s No.1 social networking site. Yahoo said that beginning on Tuesday its Internet search engine results will display up-to-the-second Tweets about various topics, matching the so-called “real time search” capabilities that Google and Microsoft announced in their own respective deals with Twitter last year. Yahoo also plans to display a live stream of Tweets within other online properties including its email service and sites devoted to sports, entertainment and finance later this year. Yahoo executives said that the company was looking at ways to make Twitter messages relevant to each property, such as by customizing the selection of messages that appear alongside an article about a particular sporting event, for example.