Google, the world's most popular search engine, has recently changed the way it displays search results. The changes made will particularly affect the way that subdomains are treated by the search engine.

In order to display the most relevant results, Google has in the past tried to group together hits from the same website. On the results page, the most relevant page of a website is displayed, with the second most relevant displayed indented beneath it. The user can then choose to view more pages from that site. In the past, it has been mainly subfolders of the same domain name which have been grouped in this way, but Google has recently made small changes to its algorithms which cause subdomains to be treated more strictly in this process. This means that where subdomains of the same domain would in the past have been shown as separate results, some will now be grouped together.

This could cause problems for some community websites, for example, which give each user a different subdomain of the main Domain Name. For example, blogs on sites such as Blogger have URLs in the form "username.blogger.com". Unlike subdomains of some domains, each subdomain under the "blogger.com" domain is run by a different webmaster and will contain very different content.

However, it is quite possible that Google has accounted for issues such as these. Webmasters should wait and see how the changes affect their results before becoming too concerned.