Unless you’ve been living under a rock, it’s pretty obvious that the advertising marketplace in America has changed radically in the past few years.

In short order, we’ve seen the largest concentration of digital advertising converge on just two players:  Google and Facebook.  In fact, according to digital advertising research firm eMarketer, those two firms alone are attracting two-thirds of all digital ad dollars in the United States.

But this development isn’t all that surprising.  The vast bulk of Google’s ad market share results from its search engine marketing platform (paid search). As for Facebook, it dominates digital display advertising not just in America, but in many other countries all over the world as well.

And both companies are the “big kahuna” players in the mobile advertising sector, too.

What’s interesting is that, despite the shortcomings that many people recognize in both types of digital advertising – banner blindness and often ill-targeted paid search results — healthy growth in both forms of advertising continues apace.

Google’s ad revenue growth has average around 20% for more than 30 straight quarters. Its growth in the third quarter of 2017 is right on pace at 22%.

For Facebook, the growth dynamics are particularly lucrative; its year-over-year ad revenue growth is pushing 50%.

Mobile ad revenues are growing even faster; they accounted for “only” $9 billion in revenues for Facebook in just the third quarter.  And just as paid search advertising revenues represent more than 90% of Google’s total company revenues, mobile advertising accounts for nearly 90% of Facebook’s overall revenues.

With so much advertising activity, one might wonder from where it’s emanating.

One answer to that question is that the “universe” of advertisers is exponentially higher than we’ve ever encountered before. With low barriers to entry and “anyone can do it” ad development tools, “Jane and John Doe” are far more likely to be advertisers in today’s world of digital marketing than was ever contemplated just a few decades ago.

To wit: Facebook estimates that its social platform has more than 6 million active advertisers participating on it at any given moment in time.  That’s the equivalent of 2% of the entire population of America.

It’s kinda true:  “We’re all advertisers now.”