A quick lesson in how the success of a site is measured for those who are unaware of it. The two primary metrics a site is measured by is “Unique Visitors” and “Page Views”. The unique visitors is the number of different people who come to a site, while page views is the number of pages each of those people visit. Each visitor accounts for one page view the second they come to the site for the first time in a month, but when they come back a second time, then they only account for another page view. Each visitor can also rack up more page views by clicking on more links within the site during a visit, or by simply reloading a page to refresh its content.

Facebook LogoWhile unique visitors are a great thing, the more page views a site can get, the better because that means the person is interested in your site, and this appeals to advertisers. Also, this means those people are exposed to that many more ads while cruising around your site.

According to Hitwise, a company that monitors Internet traffic, Facebook has now grown to account for 25 percent of all the page views in the United States. That means that one out of every four pages viewed on the Internet in this country is located somewhere on Facebook.

Personally I’ve always taken third-party measuring of a site’s traffic with a grain of salt.  While it is obvious companies such as Hitwise get it at least partially right, they do not have any measuring devices installed on Facebook to get a true count of every page view.  From my time in the blogosphere, working with numerous sites where I had access to our analytics, I have seen companies such as Hitwise and Compete really blow the true numbers, but yet people continue to turn to them for independent reporting.

With all that said, these numbers are pretty easy to believe.  Think about how many times you reload your newsfeed, go back to your wall to answer a comment, see new pictures on your friend’s profile and you can see how these numbers would add up pretty darn quickly.

In short, Facebook is huge, and probably only going to control more and more of the world’s Internet traffic, let alone the United States.