Grading blogs revisited

It seems I am catching up with my reading and my blogging. Sorry!

Aaron had a great post about grading blogs. He says

However, when we assign 'blogging' for homework and give students grades on how often they post or comment, are we not shooting ourselves in the proverbial foot? If students come to see weblogs as the latest homework delivery method, then are we not directly encouraging them to take a surface approach to the whole process?

This is so very true. And obviously, that isn't what we want to do. He goes on to say

Teachers should stop placing such a high value on quantity of posting and commenting and start honing in on the quality of social interaction.

Once again, I am in total agreement. But I am not sure what this actually looks like in the classroom and in the gradebook.

I go back to what I said earlier, that grading should be on a portfolio basis, where students pick their best posts to be part of the portfolio. I think that is critical. The criteria for inclusion could include demonstrating interaction and growth.

Having said that, however, I am at a loss as to how to actually pull that off. Somehow or other, it seems really silly to have students copy and print out blog posts and comments. But I can't see any other way to make it practical with more than a very few students. Any ideas?