Advanced comment systems are bad for SEO: IntenseDebate, Sezwho and Disqus
Bored with the out-of-the-box functionality of blog commenting, increasing numbers of bloggers seem to be turning to advanced commenting systems like Disqus, Sezwho and IntenseDebate - offering threaded comments, cross-site reputation scores and so on.
(Also, for wordpress users, wordpress 2.7 is about to introduce threaded comments).
Update 7 Nov: IntenseDebate say they are rolling out a version that works with JS off - see post below.
You can prove that google isn't indexing the comments for disqus and intensedebate by searching for the name of the person with the first comment on the page - when you do, you get no hits. (EG this search returns a results for the disqus page, not the simpable one).
Where the comments should be, you see a link that says 'View this discussion thread'. This takes you to a page on the disqus site with the comments on your blog.
This is better than nothing, as there's at least a link back to your page. But it means google thinks the content in the comments belong to disqus, not you.
Page used to test this: http://simpable.com/code/disqus/ and http://www.sexywidget.com/my_weblog/2008/08/disqus-updates.html
You lose the functionality (couldn't they have provided a static link to the info?), but at least the comments are visible.
You see a link that says 'leave a response' but nothing happens when you click it. Comments invisible to google, therefore, and also a fairly poor implementation - surely they could have made something useful happen when you click it.
Page used to test this: http://www.ultimatenoob.com/?p=425
Update 11 Jan 2009: New post on IntenseDebate and comment count.
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