[wp-hackers] Canonical & Best Practices for Paged Comment

Hendry Lee hendry.lee at gmail.com
Wed Feb 18 07:08:06 GMT 2009

> "we now support a format that allows you to publicly specify your
> preferred version of a URL. If your site has identical or vastly
> similar content that's accessible through multiple URLs, this format
> provides you with more control over the URL returned in search
> results. It also helps to make sure that properties such as link
> popularity are consolidated to your preferred version."

Also the same page


mentions that Google allow slight differences. What constitutes slight
differences? This requires a clear answer. Otherwise, as Mike said, it could
become a haven for spammers.

"Imagine someone specifying that their root is the canonical for thousands
of pages..."

Consolidating PageRank and other related signals may be abused unless Google
(and others) have clear definition about duplicate content.

With that, canonical doesn't solve every SEO problem.

A] When bloggers worry about PR distribution, they use nofollow attribute to
control the flow. But that doesn't prevent an external web site to link to
the page.


1. Page indexed by Google by following external link(s)
2. No consolidation of PR

B] Meta robots (noindex) seems to solve the indexing problem. Bloggers may
prevent search engine crawlers even there's external links.


There's still nothing that prevents the flow of PageRank to the wrong pages.
Because the page will not be indexed, the PR will go into oblivion.

Canonical transfer PageRank value and other things (Yay!). As I see it,
Google prefer this method in fighting duplicate content, instead of having
bloggers and web publishers "filter" them out.

But still PageRank flow is not optimized without nofollow.

Why would WordPress solve duplicate content problem but not optimal PR flow?
Is it because more search engines will support it?

I'm curious.


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