Grading the work students create online is new territory for a lot of teachers. Creating a well written rubric for any assignment can be time consuming even if you are familiar with the medium your students are working in. If you’re trying to create a rubric for work students are doing in a new or an unfamiliar medium the task can be downright daunting. Fortunately, there are people like Ryan Bretag who are willing to share ideas about grading the content students create online. Ryan has published, under a Creative Commons license, a rubric for grading student blogs.
By the way in case you’re not familiar with it, Rubistar from 4Teachers.org is a great place to get ideas for rubrics and create rubrics for a wide range of student work.