Today we're going back to basics. We'll be answering the question: What is a website?

...Okay, not exactly. But we will be looking into what a "website" means in the context of Webmaster Tools, what kind of sites you can add to your Webmaster Tools account, and what data you can get from different types of sites.

Why should you care? Well, the following are all questions that we've gotten from webmasters recently:

• "I know my site has lots of incoming links; why don't I see any in my Webmaster Tools account?"
• "I see sitelinks for my site in Google's search results, but when I look in Webmaster Tools it says 'No sitelinks have been generated for your site.'"
• "Why does my Top search queries report still say 'Data is not available at this time'? My site has been verified for months."

In each of these cases, the answer was the same: the data was there, but the webmaster was looking at the wrong "version" of their domain in Webmaster Tools.

A little background

The majority of tools and settings in Webmaster Tools operate on a per-site basis. This means that when you're looking at, say, the Top search queries report, you're only seeing the top search queries for a particular site. Looking at the top queries for www.example.com will show you different data than looking at the top queries for www.example.org. Makes sense, right?

Not all websites have URLs in the form www.example.com, though. Your root URL may not include the www subdomain (example.com); it may include a custom subdomain (rollergirl.example.com); or your site may live in a subfolder, for example if it's hosted on a free hosting site (www.example.com/rollergirl/). Since we want webmasters to be able to access our tools regardless of how their site is hosted, you can add any combination of domain, subdomain(s), and/or subfolder(s) as a "site" on your Webmaster Tools dashboard. Once you've verified your ownership of that site, we'll show you the information we have for that particular piece of the web, however big or small it may be. If you've verified your domain at the root level, we'll show you data for that whole domain; if you've only verified a particular subfolder or subdomain, we'll only show you data for that subfolder or subdomain. Take Blogger as an example—someone who blogs with Blogger should only be able to have access to the data for their own subdomain (googlewebmastercentral.blogspot.com), not the entire blogspot.com domain.

What some people overlook is the fact that www is actually a subdomain. It's a very, very common subdomain, and many sites serve the same content whether you access them with or without the www; but the fact remains that example.com and www.example.com are two different URLs and have the potential to serve different content. For this reason, they're considered different sites in Webmaster Tools. Since they're different sites—just like www.example.com and www.example.org—they can have different data. When you're looking at the data for www.example.com (with the www subdomain) you're not seeing the data for example.com (without the subdomain), and vice versa.

What can I do to make sure I'm seeing all my data?

• If you feel like you're missing some data, add both the www and the non-www version of your domain to your Webmaster Tools account. Take a look at the data for both sites.
• Do a site: search for your domain without the www (e.g. [site:example.com]). This should return pages from your domain and any of your indexed subdomains (www.example.com, rollergirl.example.com, etc.). You should be able to tell from the results whether your site is mainly indexed with or without the www subdomain. The version that's indexed is likely to be the version that shows the most data in your Webmaster Tools account.
• Tell us whether you prefer for your site to be indexed with or without the www by setting your preferred domain.
• Let everyone else know which version you prefer by doing a site-wide 301 redirect.

Even though example.com and www.example.com may look like identical twins, any twins will be quick to tell you that they're not actually the same person. :-) Now that you know, we urge you to give both your www and non-www sites some love in Webmaster Tools, and—as usual—to post any follow-up questions in our Webmaster Help Group.

Posted by Susan Moskwa, Webmaster Trends Analyst

1. To include highly relevant content in Google's search index. This provides a better experience for Google users who may not have known that content existed.

• To provide a promotion and discovery opportunity for publishers with restricted content.

• All users who click a Google search result to arrive at your site should be allowed to see the full text of the content they're trying to access.

• The page displayed to all users who visit from Google must be identical to the content that is shown to Googlebot.

• If a user clicks to a multi-page article, the user must be able to view the entire article. To allow this, you could display all of the content on a single page—you would need to do this for both Googlebot and for users. Alternately, you could use cookies to make sure that a user can visit each page of a multi-page article before being asked for registration or payment.