Yes, this is about the great nofollow debate. Except it's not a debate -- like Paul Kedrosky, I'll quote Matthew Skala:
I'm really concerned about anything that is sold on a pretext nobody can argue with. Nobody can speak out against fighting spam Matthew Skala: Thoughts on "nofollow"
Like John Battelle, I worry about unintended consquences:
My gut take on this yesterday was "We're making a decision without thinking through the implications." My second gut take was "We can't possibly imagine all the implications." So my third gut take is "Don't do it if we can't imagine what consequences it might have." John Batelle's Searchblog: Follow On No Follow: Will "Fully web-expressed writing" Suffer?
Spam already doesn't make it onto my site. I get lots, they sit in my approval queue, and I ignore them. So why do I care? It's not solving the problem, but it will change the structure of the searchable web.
Update: I'm going to point to Ben Hammersley for the last word on this.
Meanwhile, Scoble points out how it can be used in other ways, and undermines the second aspect of the attribute: as respecting rel="nofollow" will involve loosing an enormous amount of implicit metadata, any tools that are interested in that will be forced to ignore it. Technorati will have to choose if it’s a site that measures raw interconnectivity, or some curious High School metric of look-at-that-person-but-don’t-pay-her-any-attention that the selective use of the rel="nofollow" attribute will produce. For many purposes, this would mean the results are totally debased and close to useless. Benn Hammersley's Dangerous Precedent: Let no fellow nofollow, lest we all lie fallow
So. This won't help, it will actually aggravate the problem by shifting to non-technical blogs (arms race), thus harming the entire industry. On top of that, removing *some* outgoing links will represent a skewed view of what's going on online.
In any case, I'll be following this whole thing with interest.