I have found it helpful and cathartic to write a response to an article or comment, and then close the window without posting. In many cases it is much more rewarding than posting and viewing the train wreck that is the responses.
Agreed, although for me it is not about the responses, but about what it does for me:
If you take your posts seriously (and I generally do), you try to construct a comment that is well-written and well-founded. In that process sometimes I have to come to the conclusion that my initial reaction was wrong entirely, wrong partially, incomplete, not supported by evidence or simply an overreaction. I learn from trying to make my point and failing, without anybody ever seeing the attempt.
It's better than simulating an argument in my head because of the definitiveness of posting a comment and because I am already at the device with which I most easily (fail to) find sources/support for my arguments.
Obviously, not in this case though. ;-)