The other tactic I neglected to mention in my previous post on combatting comment spam is more big picture. How do we remove the incentive for spammers to comment spam in the first place?
Apparently the rel="nofollow" approach has done little to curb comment spammers despite many predictions (including my own). I still think it is an important step in removing one incentive, but what else can be done to remove this incentive?
With the lack of results from the rel="nofollow" approach, the lesson we learn is that either the incentive for comment spam isn’t necessarily Google rankings or that there are enough unpatched blogs out in the wild that it still does help the google rank to post comments indiscriminately. Or both.
If a spam commenter can put a link in the comments of several thousand blogs, then certainly that translates to tens to hundreds of thousands of eyeballs on that link, and maybe a few hundred clickthroughs (yes, I’m pulling these numbers out of my rear). When someone clicks through, the spammer gets paid a small amount from the owner of the site.
Warning, here is where I go off the deep end in brainstorming solutions. Forgive my naivete.
What if the marketers who pay for these links to be spread around found out that comment spammers were creating negative feelings for their products by posting comments on sites that were vehemently against having these advertisements. Would they care? Would they be interested in not paying for click throughs from sites who have specifically opted-out of such links?
I’m probably dreaming here, but stay with me for a moment as I flesh out a quick thought experiment. Suppose these sites did care. One option is for them to not pay for links that originate from sites that specifically opt-out of comment advertising. For example, by registering with some central opt-out site.
Another approach would be for sites that receive click-throughs to initiate a trackback like mechanism in which they request a comment spam policy from the blog. If the blog does not explicitely endorse their product, the link does not get paid.
Of course the big flaw in this experiment is that these sites probably do not care and wouldn't go to the trouble to implement these approaches to being a good citizen. They just want the links to come in. Even negative publicity is good publicity. So what can we do? Is there a way to make them care? Is there a way to make comment spam less lucrative?