Ask students to create a site at Blogger.com, and to post their reflections / assignments / responses / notes...whatever fits your discipline...there, in their own public space.
My theory is that it isn't simply the public nature that creates a different focus than 'assignments', it's also the ability to make scholarship so personalized (theme, colors, pics, about-me section) and the inate 'invitation to comment and critique' that is an expectation and affordance of blogging. Here's a few examples from two courses. "Try it. They like it."
1) short list of students willing to 'go public' with their blog sites for Mastering Cyberspace (IAS494):Marcy | Rick | Christopher | Maribel | Pam | Charlotte | Jonathan
2) a few of my first year students expressing new understandings from the course content of ASU101: