Ben Hammersley (h/t: VK) and Ubernostrum (h/t: LW) offer two mutually inconsistent arguments against using the “new” nofollow tags, both of which lead to the conclusion that widespread use of the nofollow tag will lead to more comment spam rather than less. Both theories can’t be right, of course, but both can be wrong, and in fact, both are. Here’s why.
First, let’s dispose of the sillier of the two theories, Ben Hammersley’s. Hammersley argues that as the use of nofollow increases, comment spam aimed at boosting page rankings will increase to compensate. The underlying fallacy, and one shared by Ubernostrum, is that he assume comment spammers are currently pulling punches to avoid spamming too many sites or to avoid boosting their Google rankings too much – and can “turn up the volume” beyond their current spammings anytime they like, at no net cost to them. I say, bollocks. Comment spammers are already spreading their spam as far and wide as they can. They’re not waiting around for someone to make comment spamming less useful, only to spam more to reach some sort of equilibrium. Hammersley utterly flunks Economics 101 with this paragraph, that pretty well sums up his theory:
So as comment spam costs absolutely nothing to spread, there’s no loss to me if I spam sites with rel=”nofollow”. It might be, at a pinch, less efficient a method of getting readership, but it will still work: and efficiency is not a factor at all. Spamming costs nothing, so spamming sites with rel=”nofollow” doesn’t bother me. I’m not losing. Perhaps I’m not winning as big, but I’m not loosing anything either. There’s no incentive for me to spam those sites for the sake of getting Pagerank, that is true, but there’s even less incentive for me *not*to*. Why would I bother even testing the site for rel=”nofollow”? I might as well just hit it and leave. It’s less work for me, for exactly the same gain (some) and exactly the same loss (none).
Got that? Comment spam isn’t just cheap; it “costs absolutely nothing” to spread. Not only that, it costs absolutely nothinger to spread it even further than they’re doing now. So why aren’t they doing it now? Also note Hammersley’s new-new math: not only does nothing equal nothing, but “some” always equals “some,” too, even when one “some” represents a small fraction of the other. O-kay.
Ubernostrum’s theory is somewhat more sophisticated than Hammersley’s, but it’s still off base. Ubernostrum concedes that of course the widespread use of nofollow will reduce the type of comment spam aimed at boosting page rankings, but argues that comment spammers will go on spamming anyway for a different purpose: to actually be read by readers. Indeed, there may be some substitution effect, but not much. Anyone who’s dealt with comment spam for an extended period of time knows that most of it is not meant to be read, or even meant to be left up long enough to be read, only to remain long enough to be “read” by a Google or Yahoo! spider. Comment spam intended to actually be read will have to be written much differently, with fewer links and a writing style that makes it look to a human as though it were part of the original discussion. This kind of comment spam is much harder to devise, more costly, and most importantly, is not a viable substitute for the kind of comment spam that has been hitting us in waves.
I have no doubt that eventually, comment spammers will find some way to render nofollow ineffective. Until they do, nofollow is a nobrainer. Unless you specifically intend to allow your commenters to boost their Google rankings or those of other linked sites merely by commenting (as Kate and Lonewacko do), there is no earthly reason not to install the nofollow option.
UPDATE: Ubernostrum responds.