Google is rumored to be adding (confirmed) a new feature to help take the bite out of comment spam: a nofollow value that you assign to a link using the rel attribute. The idea is that you would add this attribute to links outside your control—such as URLs within weblog comments or forum postings. Here’s an example link:
<a href="http://www.figby.com/" rel="nofollow">
Links with this value wouldn’t transmit PageRank, or wouldn’t be followed by Google’s crawler at all. This is similar to the vote links concept in that you could link to a site (such as a spammer you’re complaining about) without giving them a positive endorsement, at least in Google’s view.
I have some concerns about how well this is going to work:
- It needs support from all search engines, not just Google. I know most of us consider Google the most important, but the spammers would be just as happy to rank highly in MSN or Yahoo search. (update: see below)
- It needs to be the default behavior in all major weblog applications and services before it will have any impact. This is going to take a while.
- Spammers won’t get the message for a long time. Just like redirection schemes, it only works if the spammers believe it works, and that won’t happen until it’s supported across most search engines and weblog platforms. Even then, many spammers are likely to continue spamming weblogs for a year or two “just in case it helps.” Spammers are not known for their intelligence.
- Is it really fair to take away the pagerank benefits of legitimate comments?
- Dishonest webmasters will use this attribute to game the system. I’m not quite sure how, but they’ll find a way. One obvious way is to set the nofollow attribute on all external links, to prevent precious PageRank from leaking out of their sites. Whether this does any good or not is debatable, but they’ll do it anyway, and it’s bound to confuse the already-strained algorithms that produce PageRank.
I’m sure we’ll also see people who sell links based on their PageRank and then add the nofollow attribute later, making the purchased links worthless—but as far as I’m concerned, anything that hinders the widespread practice of selling links for ranking can’t be a bad thing.
Regardless, it’s a step in the right direction, and maybe someday there will be less comment spam on weblogs.
Update: Google’s official announcement has more details, including the fact that they’ve already got WordPress, Movable Type, and LiveJournal on board. Oh, and Yahoo and MSN are on board. This may just work…