Some while back, it became inessential to actually use the ‘www’ bit of the domain if your hosting company knew how to configure TLDs and subdomains correctly. After all, it is such a mouthful to say, as well, and surely everyone by now knows about the ‘www’ bit?
However, it does seem to have caused a few problems with site indexing at Google, and this week there are posts about missing data for some websites in the Google index. This could be incoming links, top search queries, or more.
If you use Google Webmaster tools (and you should) then you can easily check to see whether all versions of your domain (TLDs, www and subdomains) are being correctly indexed and the results recorded by checking the settings in your Webmaster tools dashboard. Don’t forget that your Top Level Domain is actually domain.com, and not www.domain.com, which is a subdomain.
It only takes a few minutes to ensure that all your domains are correctly included and it could make all the difference to the results you have available to you to analyse.