I'm obsessed with tagging articles in Google Reader, Pocket and Evernote and I'd like to make tags the highlight of my project. I can see Tag Reader being used by creatives who need to organize images or ideas for multiple projects, reporters who need to organize articles by news beats and even hobbyists who need to organize posts by recipe ingredient or material.
A user's most active tags populate in the left hand column where they can dragged and dropped on to the story being viewed--similar to how labels work in gmail (this function is maintained in the tablet view and accesed by a drop down menu in the mobile view). A user can see the collection by clicking on the tag--the active tag will transition to the top of the menu and the articles categorized by that tag will display in the story area. Tags can be arranged in alphabetical order or the menu can be edited by the user. Feeds are navigated from the right hand side (this panel slides away in the tablet view and is accessed by a menu in the mobile view).
Updated Framework images with grid and breakpoints: Breakpoints are represented by the color bar above the framework. I'm playing with hiding the feed and tag menus—they'll be adaptive while the story list and expanded articles will be fluid.