Google’s online dominance can now be expressed in a new way: every month, the equivalent of one seventh of the world’s population travels to their sites on the internet. Or maybe it’s every week. ComScore, the web data-mining site, recently announced that a billion unique visitors went to Google in May 2011. That’s a mind-blowing milestone, but Google seems to think they passed it long ago. In September of last year, VP Marissa Mayer said they were serving one billion users every week! Either way, we are talking about some massive traffic for the search engine giant, and they aren’t alone. According to ComScore’s estimates of monthly unique visitors, Microsoft has around 900 million, Facebook 700 million, and Yahoo about 690 million. Between them, these companies can reach and influence a huge portion of the online public which is now more than 2 billion people worldwide. As these sites continue to grow, how will the internet change with them?

Very quickly, I want to point out that while ComScore’s numbers have made the bigger splash in the media recently, their statements aren’t infallible. Far from it. These numbers are all estimates based on two million or so users (a big number, but a small fraction of the total overall), and 90 out of 100 of the largest web content publishers. However, Google itself doesn’t contribute to ComScore’s estimates, and we can’t take these numbers as certain fact. Google released their own approximation of traffic back in September that sounds like they are reaching people at four times the rate that ComScore proposes. According to VP Marrissa Mayer, they’ve already passed “One Billion Users on Google’s Sites Each Week” mark (see the video below, it’s been cued up to the remark at Google Search 2010). Whether we put more stock in ComScore’s “billion unique visitors per month” or Google’s “billion users each week” doesn’t matter as we can still draw the same conclusions about Google and its competitors: these sites are big, they’re growing, and they represent the largest shared communications we have online. Actually, considering average TV, film, and radio audiences, these companies are among the most widespread forums for communication on the planet. Period.

It’s unclear what these businesses are using that platform to say, however, besides simply asking us all to keep coming back to visit. While the business model for each of these companies is different, every one of these sites (or collection of associated sites, really) serves as a hub for communication......