SEO Dragon

Current article covers such an important concept as canonicalization. In general URL canonicalization means that webmaster provides hints to search engine helping to deal with pages with similar or duplicate content.

Example

Just a simple example. Following URLs refer to the same page:

• http://yoursite.com/
• http://www.yoursite.com/
• http://yoursite.com/index.php
• http://www.yoursite.com/index.php

But technically all listed URL are different. Canonicalization, whether done by webmaster or a search engine, refers to an action of picking the best URL.

Why smart search engines can’t handle it themselves?

Actually they can, but not always the way webmaster intended. Give it a thought: search engine might have downloaded those pages in different moments of time and considered them to be different. Probably in time they are going to be stuck together, but they might be not.

Why should webmaster care of these issues?

There are several reasons for canonicalization:

• It ensures that user lands to a page you designated to be the main version. For example most of the forums have an option to generate page version intended for printing. Its contents are usually the same as compared to the main version, but those pages are not totally alike. Canonicalization would help search engines to index the proper version, so your visitors go to the right page from search results.
• All rankings are consolidated to the main version of the page, which means additional benefits from internal linking.
• It helps to decrease number of pages with “N/A” pagerank, which may be irritating.

How to implement canonicalization in practice?

• Use redirect 301 (moved permanently) for the pages, which are the same following the logic of your website. First thing to do here is to choose between www and non-www. Also ensure, that all pages on your site has a single version whether with trailing slash or without it.
• If page was moved, manage to add a 301 redirect from old URL to a new destination.
• If page was deleted, whether serve a 404 on that page or put a redirect to a similar one.
• Close auxillary pages and directories from being indexed using robots.txt file.
• For pages with similar content (print pages, pages with the same content in different order, etc) use canonical tag.

Conclusion

I hope that post helped you making your website friendlier to search engines and acquire better rankings using such on-site technique as canonicalization.