Don’t quote me on this, but my hunch is that using absolute links are best because shows the search engine the definitive, unchanging location of the content you are linking to…. and there is no change of confuse it with aliases and abbreviated versions. For instance, if a content management system uses dynamic URLs with lots of parameters.. the search engine crawler might not understand that ../index.html , and http://example.com/1.html and http://example.com/load page=?id=1 are the same content. Linking with the absolute URL reduces the chance for confusion and internal link dilution.

Thanks very much anyway

Apologies for not picking this one up – I see no-one has gotten back to you about this. You’ve actually mis-quoted the question slightly which may be why you’re not seeing the answer

The question from SEOmoz was as follows:

“Why are absolute (http://www.mysite.com/my-category)URLs better than relative (“/my-category”) URLs for on-page INTERNAL linking?”

And the answer from SEOmoz as follows:

“Correct Answer: When scraped and copied on other domains, they provide a link back to the website

None of the answers makes sense, except that which refers to scrapers, who often copy pages without changing links and will thus link back to your site, helping to reduce duplicate content issues, and potentially provide some link value as well.”

Which I think I pretty much agree with. It also reduces the impact of any duplicate content issues you might have due to multiple domains resolving to the same content.

Hope that answers your question!