Before there was Airbnb, pre-Uber and prior to Netflix’s response to those household cries of “Why is there nothing good on TV?” brand strategy focused on the notion of best practice.

It made sense, it worked, and it was how conventions in brand advertising, design and consumer experiences were formed. By following a best practice formula, brands emulated the category leader and remained largely out-resourced and unable to alter the status quo.

Over the past decade, however, challenger brand strategies have changed all that.

The companies taking to the stage tomorrow and Thursday during the inaugural Brandweek Challenger Brand summit are following in the footsteps of brand pioneers before them by fighting inertia, introducing a new criterion of choice into categories once dominated by an unmovable market leader and by adopting a strong belief into how those categories should be.

Brandweek’s lineup of challenger brands show an absolute conviction for change, which helps fuel a relentless stream of innovations, large and small.

Eatbigfish, a leader in work on Challenger Brand theory, distinguishes challengers from disruptors by this belief and conviction. The disruptor often relies on advancements in technology whereas challengers use ideology. This ideology determines where challengers focus their disruption, helping them apply effort to where it matters most, according to their worldview.

Take Harry’s, for example. The best practice market leader approach of claiming that a shave is “the best a man can get” and then delivering an expensive razor, on a par with dozens of seemingly undifferentiated models with names like Turbo and Mach, resulted in category stagnation. Harry’s ideology is that consumers don’t really need as much choice as they’re being offered when it comes to razors. For it to achieve relevance, it just had to offer one type of product made by people passionate about shaving.

Casper (who, together with Harry’s, will be speaking at Challenger Brands), adopted a similar ideology. According to co-founder and COO Neil Parikh, whose father is a sleep doctor, the mattress industry was a racket, with salesman offering 35 different models, which were basically the same product but with different labels.

Casper grew trust by eliminating the unnecessary category choices and communicating its passion and expertise for a single kind of mattress, which combines the two materials consumers tend to prefer above others: foam and latex. It was a strategy that helped get Casper to $1 million in sales during its first month and $100 million within its first two years. And just like Harry’s, the strategy creates a more elegant path to brand trustworthiness as it improves people’s lives by removing complexity while saving them money.

Another reason challenger thinking has become so important to broad range of brands—whether they be legacy, incumbents or scrappy startups—is the rise of Amazon in a world made more turbulent by political, environmental and societal upheaval. Amazon’s disruptive influence across categories has seen it amass so much power, brand influence and change many aspects of consumer behavior that it is unprecedented in the history of our society.

Amazon doesn’t discriminate. It competes with every brand on sales, product search, display advertising, retargeting, product development, original content, delivery, customer retention and a raft of other marketing facets. But the one thing Amazon can’t compete on is ideology. To challenge Amazon’s vision of global consumerism, brands of all shapes and sizes are finding more meaningful ways to make themselves more distinctive.

In a turbulent world where one platform is bidding to rule them all, there’s a growing army of brands intent on changing the way we think, how we behave and how we make our brand choices, all for the better. Today it’s not the best practice that’s stagnating categories; it’s something much bigger that’s threatening category decline. Brands with ideology and who adopt a challenger mentality can make a difference and can fight back.