I recently had one of our tech savvy students come to the lab to print an assignment for a teacher.  Due to the fact that I have been preaching paperless, I am a typically surly tech guy, had only one cup of coffee and knew the student well enough I proceeded to lambaste the child for daring to print an assignment, much less in my presence.
She politely responded “My teacher told me to print it.”
I retorted, “Your a techie, why didn’t you just share it with her for her to see and comment.”
She replied like a well trained general in my legion, “I shared it wiith my teacher but she asked me to print it instead.”  My head screamed, “AAAHHHHH!”
Just then her teacher came in and I asked her the same thing and she replied, “I know i should do that but it takes me so much longer to grade their writing on Google Docs than on paper.  I don’t have time for that.”
Despite that I had many a retort for that answer, the problem with tech adoption lies in her gripe exactly.  Why would teachers use tech if it makes it slower or less effective?  So many a naysayer will come along and rightfully say that the old method is still better than whatever new-fangled technology can offer.  Now I cannot expect this teacher, but hopefully eventually inspire, to be willing to seek out the tools that would make it easier so that she could meet the students where they are comfortable and working well, so I must take it upon myself.  As the tech guy of many years I have now calmed the storm and answered all of the usual issues ( the network is stable, the printer works, the projector is mirroring and the coffee maker is plugged in) so I can safely tackle the true problems that are plaguing the teachers I work with.
So in the efforts to best help this one teacher reach her goal of simplifying the grading of writing I have compiled this list of tools.  The ideas of tools below allow a teacher to grade without having a printed copy.  Hopefully a few more teachers can take a step towards the paperless classroom while also freeing up their own time to do more than just correct papers.
This is putting aside the arguments of grading or not to grade and whether teachers should be using red pens or not. Those are all fun arguments but for another time and place. 
Commenting
We start with the most obvious format of commenting. Most schools have found their way into the world of GAFE and the digitizing of the same work they have done on paper for years. What is remarkable is the ability to have a dialogue between students and teachers or students with peers and to be able to do this in a “living document.”
Ok, OK we know it is cool but how do we do it?
When a student shares a document with you or you pull it up in Google Classroom you can highlight the text that you want to comment on and then you can leave a comment using one of the three methods below:
1) click on Comments in the top right corner then on Comment.
Screen Shot 2015-09-16 at 10.11.47 PM
2) Click on Insert. Then on Comment.
Screen Shot 2015-09-16 at 10.09.58 PM
3.  Hold down the Control key, the Alt key and click M (PC/Chromebook) or Command + Option + M (Mac)
This is my personal favorite as I love to take advantage of key combinations to reduce the clicking and increase my speed.  Alice Keeler has a great workflow for correcting papers this way.
Once the comments are in then the student can work through the suggestions and click resolve as they complete the revision.  Now they have a document much more fit for your eyes and the rest of the world.
 
Short Codes
Some teachers see how cool commenting is and get into it only to find that it takes more time to type than to write by pen.  That can be the case for some and so for those teachers we can use short codes.  In general correction of writing there are standard symbols and abbreviations that teachers use to get the point across for grammar or things like that. Even in mathematical writing a teacher may comment on the lack of process or labeling solutions and so abbreviations can be used to make the grading go quicker as well as provide students with a consistent feedback protocol.  This can be applied to commenting as well.  Dropping in some well know abbreviations instead of full on sentences can get to the point as well as make the grading a bit faster.
Voice
Kaizena
Some folks might think that even the short codes take too much time so we move into the least amount of typing possible; the voice comment.  There are many ways to do this but the most popular is  Kaizena.  After connecting this to your drive account you can simply add a voice comment the way you would add any other comment. Most of us can talk with great ease so we can rifle through a group of writing in no time.
Annotate

iAnnotate

For those that really can’t let go of the pen but still want to embrace the tech then maybe annotating the document is for you.  Using a tool like iAnnotate will allow you to pull up the student work and using a stylus or your finger, mark up that text all you want.  Then that can be shared back to the student.  This may be less effective as a tool for dialogue but a great substation for a red pen.
The next two ideas really take the cake for me because they exemplify the growth mindset and the working towards mastery while also taking full advantage of what technology can do to expand the limits of the classroom.  
Blog
What if we take the idea of the writing assignment and looked at it like more of a process.  It is a process that needs to be exercised constantly and with frequent feedback.  What better way than for students to get into the habit of writing daily and to have their peers, the teacher and the world available for feedback.  Take that same assignment and put it in a post and have students and the teacher all comment on it.  The practice and the peer revision is key to developing better writers so why not take advantage of that and publish it out to the class or the world. The teacher can still comment on each student but they will likely get a lot more help since so many eyes are looking at it.
To develop that kind of culture in your class takes a bit of effort but the work up front will pay dividends for a long time.  There are many online products that allow for granular control of student blogs if the real world of the internet is too daunting.  Start with Edublogs or Kidblog and see where it takes your writers.
The Community Writing Project
Marin Catholic Community Writing Project
This has to be my favorite example of using all the tools available to get students writing towards mastery.  The project was started at Marin Catholic High School by Principal Chris Vladez.  Having been an English teacher for years he had helped more than a few students edit their college essays.  Seeing that many of the application questions were of a similar type he started to teach and focus the student writing on situations where those same styles would appear.  Eventually as principal he applied these writing styles to essays written in many disciplines throughout the school giving students plenty of practice in writing these kinds of essays.  The students would end up writing more of these essays over their 4 years of school and it seem a daunting task for any teacher to have to grade all of those but here is where the genius comes in.  The process boils down to these  simple steps.
1. Student writes essay.
2. Peer reviews it and suggests corrections.
3. Student revises it.
4. Student shares revision with another peer.
5. Student revises it.
6. Student shares new revision with 3 community members.
7. Student take in all suggestions and revises it again.
8. Teacher sees near finished version.
9. Student revises if showing less than mastery.
The genius lies in first getting the student to revise based on the many eyes of the people vested in that student’s success as well as not having the teacher see it until much later in the process.  It is a lot easier to grade a bunch of near perfect papers than to have to sift through all of the simple mistakes that someone else can pickup.  It is also genius to find people in the community that would be willing to help the young writers. What a great way to involve donors and alumni as well as build a better writing program.  My wife had the joy of participating and it was amazing to see the progress of these kids.
It sounds like a lot of work but you can easily find a few folks that would be willing to help students along with suggestions.  If nothing else the lesson of having many eyes share in the revision process before the teacher ever sees a version.  Such a great model.
Many More? 
I am sure i missed some of the ways that teachers can grade without printing.  I hope you will help me finish out the list in the comments below.  Try some of these out in your own classroom and be sure to share the process with all of us.