One year ago, Facebook unleashed the Like Button to the internet community at the f8 conference.  The Like Button, of course, allows people to share third party content that they find interesting, funny or for which they have some sort of affinity.

The Like Button sprung out of Facebook’s old “Share” button that pretty much did the same thing but was a little more clunky in its operation.  The Like Button is a one-click way to share your favorite content, much more streamlined than website-generated “Add This on Facebook” buttons.

Of course, Facebook didn’t just create the Like Button to facilitate our sharing of cat videos with friends.  The Like Button is constant and ingrained advertising for Facebook.  It has become so deeply embedded in our societal consciousness that we sometimes don’t even realize how much it has permeated our culture.

Inside Facebook relays some stats about the Like Button, one year in.  Over 2.5 million websites have integrated with the Facebook Like Button.  According to comScore, that includes all of the top 10 sports sites, 9 out of the top ten news sites, 9 out of the top ten entertainment sites and 18 out of the top 25 retails sites.  Overall, 80% of the United States’ comScore top websites are fully integrated.  Every day, 10,000 more add the Like Button.  And what happens to the sites that adopt the Like Button? On average they see a 300% increase in referral traffic from Facebook.

Though just in its infancy, the Like Button is already everywhere.  It is an indelible part of our online experience.  If your site doesn’t integrate with Facebook, then you are now in the severe minority.