Facebook's ad boss half-apologizes to advertisers

On stage at Techcrunch Disrupt, Facebook's ad chief Andrew "Boz" Bosworth gave a half-apology to advertisers for changing the rules on them.

"I wish we could go back years and change the pitch we brought to advertisers. We really didn't anticipate the speed of our own growth and the competition it would put in the newsfeed," Boz said.

See, Facebook has always been about the "Like." You like your friend's status and you like your favorite restaurant's page.

The "like" used to the most powerful tool for brands to reach customers, too. Companies would measure their advertising success based on the number of likes they had and the number of people they could reach because of it. As a result, many companies invested time and money to gain those likes and build up their Facebook empires. It was a free way to talk to thousands of people, and a powerful tool for many advertisers.

Just think of all those ads that begged users to like their pages to receive promotions.

But over the last couple of years, Facebook has tweaked how the Newsfeed works, and businesses lost traffic to their pages. To regain that traffic, many have bought different kinds of ads.

On stage, Boz explained what changed: Years ago, Facebook didn't have the technology to measure all the way to a business result like a sale, he explained. Instead it gave out these "proxy metrics" like page likes and social reach - it's literally all they had to sell, Boz said.

However, he still believes those investments were good investments and did pay off for many businesses.

"For us, when you think about the size of pages on Facebook's ecosystem, there's 45 million active business pages. Only two million of those are advertising," Boz said. "So, 43 million are finding value in the system without advertising and that's only grown over time."