(This is a rough screen cast that I recorded when I had the flu. I plan to re-record it when I get some free time.)

You will need to install both the Doctopus add-on and the Goobric Web App Launcher. I especially like the auto advance feature.

Teachers can get the premium version for FREE. I mainly use the voice commenting feature. It will insert your voice comment into a comment bubble.

Students do not have to have Read&Write installed to hear your comments. However, they can use the text-to-speech function (free) to listen to their work.

Draftback allows you to see the development of the document. Great for checking for plagarism and time-on-task.

Highlight and record a voice comment without leaving Google Docs Kaizena now has a Lessons feature, which lets you attach saved feedback to highlights inside a Google Doc. You can also track student skills with their new Skills feature.

From TextHelp, the makers of Read&Write. Writing assessment add-on uses machine learning to grade your students' work. It has a built in rubric function. It is still early days, and they want teachers to use this to grade written work so that they can anonymously gather data on common student errors. Teachers who participate will get WriQ free for life. TextHelp plans to develop a "Lexile"-type score for writing based on this data.

It is worth checking out. I found many false positive and misclassified errors when I tried it when it first came out.