I really enjoyed Clive Thompson's discussion of public writing in the "Digital School" chapter of Smarter Than You Think. It's really interesting how the high school students described in the book treated writing in an online public forum completely differently than writing a paper for a teacher's eyes only. The most compelling difference for me was the ownership the students took over their writing when they knew it could be read by the public.
The idea of strangers reading their writing caused the students to be more interested in writing in general, work harder to perfect their posts in terms of grammar and style, and even helped them better understand what it means to write for different audiences, as evidenced by the example of the student who commented (in a discussion about the New Zealand rugby team), "People in America won't know what the 'All Blacks' are" (186) on his peer's post, indicating his understanding of a global audience (Thompson calls this "digital citizenship" ). And the students' writing really did show improvement in test scores, which, as Thompson notes, are what matters in the educational system. Public writing works.
My own experiences agree with Thompson's example. I've found that I automatically take more ownership of my writing when I know that it will be available to the public. In the English department at Clemson, many professors require students to post on a public or semi-public forum weekly (this class is an obvious example). This act of writing about what we are reading or studying for an audience of our peers, at the least, and possibly a much wider audience, always inspired me to try harder to say something intelligent or insightful (or at least get my facts straight) than I might if my professor was the only audience. Writing something when you know lots of people will read it brings a certain amount of "pressure" along with it, and helps us take more pride in our work, which I think is a great thing.