The argument behind rel=”nofollow” was that spammers were trying to game the system to get link credibility for thier sites. Having a way to flag links that haven’t been human-reviewed so that they don’t count toward PageRank (and similar algorithms) would remove that incentive, and spammers would go away.
Fat chance. You haven’t noticed it here because of moderation (a similar way of enforcing human-review and removing incentive to game the system), but the spammers have already been hammering this site. A 3-second check would show that their efforts aren’t working, but if someone has a bot slamming thousands or millions of sites, apparently it’s not even economical for them to direct their spew–they keep on trying.
Even as the dis-incentives pile on, levels of spam activity increase. Nofollow doesn’t work, because it doesn’t live at the same level where the problem occurs. Comments? -m
Have you considered adding a non-standard field for the results of some sort of CAPTCHA to your comment form? You could post a simple image and ask the commenter to supply the (English) name of whatever was pictured or (easier for non-native-English-speakers) ask the commenter to perform some simple arithmetic and add checking for the correct answer to the bit of comment form processing code in WordPress.
It’s simpler to implement than image CAPTCHA, less easy for spammers to clip out and integrate into porn or whatever sites for their visitors to answer for them than one of the widely-implemented image CAPTCHAs, etc.
After adding a math question and checking to my hacked-up installation of WP, comment spamming (for me) ceased. In a year or so, I believe that I’ve had one real live human spammer chuck crap into my comment moderation queue and he gave up after noticing that none of his comments every went live on my blog.
I’ve also turned off trackbacks for obvious reasons.
Personally, I think it’s only fair that someone leaving a legitimate comment gets some PR recognition for a minute or two of their time.
As for spam, we just have to deal with it as it comes. There’s no “easy†way to get rid of it.