interesting; http://www.seomoz.org/blog/using-canonical-tag-to-get-more-than-one-anchor-text-value-11283
not sure if its actually useful, but could come in handy!
More on nofollow and anchor text passing:
http://www.socialseo.com/blog/an-experiment-nofollow-links-do-pass-value-and-rankings-in-google.html
Seems nofollow will pass pr to some extend. Anybody seeing the same?
I've never done a pure nofollow experiment, but common sense and a lot of gossip dictates there's benefit passed by them, more than a 'natural' profile.
I pretty much work on the basis they're worth 50% of a dofollow link of the same quality/placement. Not sure how well that would work on a competitive keyword though - don't think you'd get poker or viagra rankings purely from comment spam these days?
Adde parum parvo, magnus acervus erit - Add a little to a little, and there will be a great heap