This plugin adds OEmbed-style embedding of Yahoo Screen videos.
Paste the URL of a video’s Yahoo Screen page on a blank line by itself, save, and an embed will appear in its place on the front end. No need for any HTML code: it just works.
(The technical bit: Yahoo Screen allows embeds by appending ?format=embed on the end of the video page URL, this plugin handles that for you, retrieving the embed code and showing it to your site visitors.)