If you want to read an article, but do not want to share this activity with your friends, you can turn sharing off prior to viewing an article by selecting Off from the “Social” drop-down menu under “You on Yahoo!”. Remember to select On from the “Social” drop-down to resume sharing your reading activity.
If you have already viewed an article and wish to remove it from your reading activity, open the Your Activity drop-down under “You on Yahoo!" and click the X next to the article. Deleting an article will also remove it from your Facebook feed.