I disagree with many of your statements. What's to prevent a student from posting a plagiarized rough draft on his/her blog (or one written by someone else). Also, not giving tests is not feasible, in the sense that less people are able to cheat on tests than on homework (or other forms of evaluation where they're not supervised)
Thanks for the comments, Sam; here are some practical classroom techniques that might alleviate some of your concerns.
First: on the issue of plagiarizing a rough draft. I have my kids do the majority of their prep work (collecting and evaluating sources, etc) and do the writing of the majority of their rough edits during class. That way, I can roam around and chat with them about their work as they are doing it. This personalized approach goes a long way towards fostering mutual respect. And as I've said before -- particularly with regards to graded blogging -- the kids by-and-large find cheating on blogs to be way lame. It's a matter of finding a balance between tone, attitude, and personal responsibility for one's work.
In terms of your second concern, about the non-feasibility of not giving tests, please suffer this brief anecdote; I understand that personal tales aren't always the best way to demonstrate a point, but I offer this one nonetheless.
Last year I decided to can our AP Art History curriculum (or more precisely the manner by which we approached that curriculum) and start new. I'd taught the course for a few years and although students seemed to enjoy it very much, they always earned marks well below the national average on the AP exam.
Now, the way I used to teach the course was by lecture with weekly slide ID tests -- much as I myself had learned Art History in college.
Well, as a new approach, I decided to can the tests.
Instead, I opened up our classes to more casual conversation about the material ("conversation" as a way of describing class actually came from a student and not me).
And then I replaced weekly tests with bi-weekly blogging.
And guess what?
Every student passed the AP exam and my average beat the nationals.
All without giving tests.
And did I mention to say that there are no prerequisites to get into my AP Art History class? That is, I never cut a student from the roster based on previous academic work; instead I tell them that if they are interested in Art History, then this is the place to be.
So this wasn't a class of "geniuses"; rather it was a class of kids of all academic stripes who loved art.
As for the reader's concern that "less people are able to cheat on tests than on homework (or other forms of evaluation where they're not supervised)", well I'd just have to say that not giving tests forces you to give assignments and approach material in ways that are more open and less "cheatable".
After all: building a quality and authentic assessment is part of what teaching is all about.