Tagging content (or, in technical terms, adding descriptive metadata to data) started out as way to dynamically format the same text differently for different purposes. Now, tagging is often used to make subsets or chunks of content identifiable and findable by different audiences with different needs. Two pioneering organizations, WGBH and HP, have significant initiatives underway that demonstrate the importance of tagging content for meaning. These organizations demonstrate how subject matter experts can drive the outside-in perspective for categorizing content in an intuitive and meaningful way.