Fighting Weblog Spam with rel="nofollow"
I’ve been logging in to my blog software every morning recently. Not to post, mind you, but to see if I’ve been hit with yet another round of porn-and-gambling spam. The plugins I’m using — Spam Karma for WordPress and MT-Blacklist for Movable Type — have been doing a pretty good job at fighting the spammers off, but lately they’ve needed more manual supervision for those occasional comments that slip through.
This may be changing, however, with yesterday’s announcement of a joint venture between Six Apart and several search engine companies that is aimed at eliminating a major motivation behind comment spam: the accumulation of search engine rank thanks to all the spammed links to their pages. Introducing rel="nofollow", an attribute that can be added to any hyperlink to prevent search engines from following and indexing that link. This deprives spammers of their Google juice, and greatly decreases their incentive to spam your weblog. Six Apart’s Jay Allen, author of the MT-Blacklist anti-spam plugin, explains it this way:
The initiative is based upon the idea of taking away the value of user-submitted links in determining search rankings. By placing
rel="nofollow"into the hyperlink tags of user-submitted feedback, search engines will ignore those links for the purposes of ranking (e.g. PageRank) and will not follow them when spidering a site.For you Movable Type users, we packaged that change up into a plugin. Drop that baby into your plugin directory, sit back and pop open a beer. You’re done.
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Those of you who display referrers on your site will want to modify your scripts to include
rel="nofollow"to get the same effect.
Sounds great, but won’t this tactic cause the PageRank of bloggers everywhere to plummet? In a word: yes. Jay argues that this is a small sacrifice to make in order to start choking off a phenomenon that threatens to kill blogging itself, much like e-mail spam is threatening that medium:
Now, the astute will point out that because links in comments/TrackBacks are ignored by the search bots, the PageRank of bloggers all around the blooog-o-sphere will suffer because hundreds of thousands of comments linking back to their own sites will no longer count in the rankings. And that is most likely true. But that inflated PageRank, which was a problem created by the search engines themselves, is the rotting flesh that the maggots sought out in the first place. If you ask me, I say fair trade.
Jay lists Google, Yahoo!, and MSN Search as being the search engine companies adopting this anti-spam measure. According to various announcements from the participating parties (check out “see also” at the bottom of this entry), the following blogware will support the new attribute value: Six Apart products (LiveJournal, TypePad, Movable Type), Blogger, WordPress, Flickr, Buzznet, Blosxom, Blojsom, and MSN Spaces.
Reaction from around the blogosphere has been skeptical and mixed. My favorite so far is Mark from Weblog Tools Collection, who thinks the whole thing might just be a conspiracy.
(see also: Yahoo’s announcement on their search blog, Google’s announcement, Microsoft’s announcement, Scoble’s post on MSN Spaces support for nofollow, and ongoing coverage at threadwatch.org)

