Over the past few years, Mozilla has emerged as a company dedicated to the privacy of its users. It’s going to take that to the next level with Firefox 22 as the browser will start blocking cookies by default. The ad industry isn’t particularly happy about it.

The Interactive Advertising Bureau sent out a press release this week claiming that Mozilla is “undermining American small business” by choosing to block cookies by default. The group says that the makers of Firefox are also undermining consumer choice by automatically blocking cookies, instead of giving users a choice.

“Thousands of small businesses that make up the diversity of content and services online will be forced to close their doors,” said Randall Rothenberg, President and CEO, IAB. “This move will not put the interest of users first. Nor does it promote transparency or ‘move the web forward’ as Mozilla claims in its announcement. It will not advance Mozilla Corporation’s objective, as stated in its bylaws, of ‘promoting choice and innovation on the internet,’ but will, instead, impede both.”

As Consumer Affairs points out, Firefox isn’t the first browser to block third-party cookies by default. Apple’s Safari has been doing it for quite a while as well. It’s also not like Mozilla will be blocking all cookies anyway. It will only be blocking cookies from Web sites that users don’t frequently visit. What that means is a user’s one time visit to a blog covering the world of decorative dog sweaters won’t see any tracking cookies installed on their browser.

This isn’t the first or last time that advertisers will be upset with browser makers over controversial pro-privacy practices. Microsoft was caught in the middle of a controversy last year over its decision to make Do Not Track the default option in Internet Explorer 10. That decision has yet to break the Web or online advertisers, and Mozilla’s move will probably not affect much either.

That being said, advertising has a valid purpose on the Internet, and shouldn’t be blocked just because. Many of the things we enjoy for free are paid for with advertising. That’s why there needs to be choice in the matter, and Mozilla will hopefully make that choice clear when it starts to block third-party cookies by default later this year.