Canonicalization is a relatively new term introduced in the realm of search engine marketing as a way to describe how website URLs are formed. It is the process of picking the best url when there are several choices, and it usually refers to home pages. For example, if your website’s homepage is www.abc.com, it may also come in other forms such as www.abc.com/index.html or abc.com (without the www prefix). Search engines (particularly Google) try to pick the url that seems like the best represents the set of URLs.
But even before search engines get the opportunity to figure it out, are we sure we make our homepage accessible through these variation of URL formats? Let’s take a look at the following Hong Kong government websites. While this does not apply to all, there are websites that don’t display the homepage using the non-www format.
Department of Health
Leisure and Cultural Services Department
I didn’t review most of the others because I think you get the point. The impact of a non-functional URL (no WWW, that is) is not much for search engines; they surely won’t pick URLs that don’t display content. The issue is more about potential missing out on lots of inbound links. Think about other websites linking to non-www versions of sites. For example, if I want to link to CNN website and use cnn.com because it’s a shorter URL. If cnn.com doesn’t work then my link won’t work, and CNN website miss out on possible floodgate of visitors reaching its site using the cnn.com link.
If we have preference on what URL you’d like Google to pick up, Google Webmaster tools can help you set it up.
Or you can also use that preferred URL format consistently into your website to ensure that version gets picked up easily.