Hinted to a few days ago, it's now official: Google has done something to prevent comment spam and they're being followed by MSN Search, Yahoo!, Six Apart and more than ten blog software editors. At last some real response to this plague!
How does this works? You just have to add an attribute rel="nofollow" to untrusted links, like this:
Visit my <a href="http://www.example.com/" rel="nofollow">discount pharmaceuticals</a> site.
With this attribute, search engines will not value this link and it will have no influence whatsoever on its ranking, effectively removing all incentive for spammers to leave links on your site.
For Movable Type, you can download the 'nofollow' plugin to implement this automatically in your MT blog. TypePad will be updated tomorrow followed by LiveJournal (no ETA though).
A few thoughts:
- this will have an interesting side effect on the ranking of blogs in Google and alike. Those blogs that have gained PageRank only via links into comments will loose it. I bet some people will like it this way, others won't, but some of the criticism that blogs are over ranked in search engines will be void
- this method is not just for blogs, consider it a new thing in your webmaster arsenal that can be applied anywhere it makes sense (web sites, wikis, forums, guestboards, whatever...)
- this will be effective only when a vast majority of sites will have applied this method. OTHO big blogs farms such as LiveJournal, TypePad, Blogger and MSN Spaces will roll it out asap and this will have a quick impact
- watch for people seeking for SE rank to start asking for "valid links" on your blog!
- I don't find it clear* from the post on Google Blog if Google does not follow the link or simply drops any PageRank value in the journey. If the latter, the semantic of this tag is misleading as it is the contrary of the
META nofollowrule that can be applied to a page and effectively prevents SE to follow all links on the page
(*) From Google:
when Google sees the attribute (rel="nofollow") on hyperlinks, those links won't get any credit when we rank websites in our search results
This just tells us that no PageRank is transferred then, but we don't know if Google follows the link or not.
Q: Should I put rel="nofollow" on the link to my comments page?
A: Probably not, because lots of interesting discussion can happen there.
This tends to suggest that Google would not follow a link with rel="nofollow", which would be the correct behavior, frankly. Google should update their post to clarify this point.
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I don't think it is a good idea not to follow at all the link, because the SE will certainly loose some content which can be interessant, although the author of the link think it does not deserve PageRank.
Therefore there should be a strict nofollow (which indicate some content not to index at all) and a looser one (I don't find a good name, but nopagerank could be a start) that permits following and indexing but without any PageRank.
Adam, I disagree, I think the incentive for a user to post is the PageRank so if they are not getting it. There is less chance of them posting, blogs which will give you pagerank for replying are sure to get more comments.