Kaizena is a great add-on for Google Documents and Google Presentations. Kaizena allows you to add voice comments to Google Documents and Presentations that are shared with you. Earlier this month a notification feature was added to Kaizena. Today, Kaizena added a feedback tagging option.
Kaizena tags allow you to select a portion of a document or presentation at tag it with a skill, a Common Core standard, or an element from a rubric.
Kaizena can be added to your Google Documents through the Add-ons menu in Google Drive.
Applications for Education
Tags can be combined with voice comments. Use voice comments to explain to students how they met a standard that you have tagged in one of their documents or presentations.