As an editor when editing an article, I should be able to select multiple filters(tags) from any category that apply to the article, such that user can select the same filters and see only that set of articles

[romichg]

For example, an article can apply to both PHP and Web Application. As discussed here: TeamMentor/TM_4_0_Design#472 (comment) an editor should be able to apply those two filters to the article and when browsing or searching a user should be able to select PHP and Web Applicatoin to see that article.