I can't say how powerful this method is, but it got me at least 100 backlinks from wordpress.com http://ilkince.net/2008/02/06/an-interesting-backlinking-method/ (posted a link to prevent duplicate content) I hope this helps someone, and I hope someone can figure out how reliable and useful this method really it.
This seems like the same thing as adding technorati tags. I've been using them for over a year and can't tell if they do anything, they may help a little.
What's odd is that technorati tags never really helped me out much at all. I don't even see them coming through as backlinks. That's why this interested me.
I'm not sure how valuable these links are, but hey there are for free and coming from a trusted site!