I read this interesting post by Darryl VanDorp:
Hey people new to this whole blog thing. If you want me to actually leave a comment on that new blog of yours. Turn off that damn default nofollow in your shiny wordpress installation ... If I take the time to leave a comment give me some juice!
I quite agree. Yes, I know nofollow came about as a way to discourage Weblog spammers, but I don't believe it will ever work. It is just too easy to write robots that leave comment spam, and unless 100% of systems use nofollow, which is never likely, it will always be worth the spammers' while to keep trying on the off chance that they find sites without nofollow. Also, spammers are probably happy to have their messages on Weblogs, google juice or no.
Look, we don't want comment spam on Copia, period. It's not enough to deprive them of google juice. We work to keep the site spam-free. All comments go in an approval queue, and we have a lot of handy little tools to help eliminate comment spam, so we can batch approve the remaining goodness. I think this takes a lot less effort than the actual work of composing entries on the blog (and I'm a fast writer). What's more relevant, it's less effort than it takes for visitors to compose their comments. As a result of this effort there is no need to use nofollow on Copia, and we don't do so. I don't know whether commenters get significant juice from Copia, but what juice we do have to give we shall not stint our correspondents. (Not even if they are here to engage in the heresy of disputing our positions.)
I can't help thinking of the gardening analogy. If you want a nice garden, you have to roll up your sleeves and pull up your weeds. There is no quick fix to preventing weeds: the conditions that make your soil attractive for germination of desirable flowers also make it attractive to Uncle Darwin's rogues.