As a relatively new channel, digital has disrupted a media landscape that was previously dominated by television, print, and radio for decades.

The upside is clear: digital provides marketers with many ways to reach consumers via social media, display advertising, content marketing, and more.

But within social media alone, there are a dizzying array of platforms to use to keep up with customers — Facebook, Twitter, Pinterest, Instagram, LinkedIn, and YouTube, to name a few.

Each platform requires a nuanced approach to brand voice, different metrics to capture and review, and different insights to derive. There's a lot of information to parse through.

And beyond that, it seems like customers have more control than ever before.

An unhappy customer used to tell a friend about her negative restaurant experience, but now she can write a review on Yelp and share it with thousands of readers.

Customers can also take over marketing campaigns that derail the most well-planned strategies, as was the case with McDonald's and their #McDStories hashtag.

It was a prime example of crowd-sourced content gone wrong. Instead of heart-warming nostalgic stories, people tweeted dozens of comments like this:

McDonald's originally promoted the hashtag, but quickly pulled the campaign within 2 hours.

So we can agree that more than ever, a marketer's job is complex, with more to do and less control about how campaigns will run once they go live. And at the rapid pace that technology is evolving, the trend isn't likely to reverse.

So how can marketers regain control of an increasingly busy, fragmented, complex digital landscape?

The answer lies in embracing agility. The same real-time web that allows customers to post and share content with friends, whether it's positive or negative for your brand, also offers marketers the ability to act quickly, try new ideas, and fix mistakes fast.

Even for Fortune 500 companies, this level of flexibility and agility means that brands can instantly do more of what works well, and less of what doesn't.

In other words, brands can practice optimizing their creative and messaging in ways that weren't possible before.

For example, we can look at how this plays out for one facet of digital marketing: display advertising. Marketers spent almost $15 billion on display advertising in the US in 2012, so this is a big part of the brand budget.

Within display, brands can be agile by leveraging paid media publishing to publish relevant content — such as recipes or streaming news feeds — directly into display ads.

By testing a variety of creatives, marketers can see what's resonating with users, then increase the frequency of the most successful versions of ads. This allows marketers to impact the ROI while the campaign is ongoing, not just to review it when it's over.

Making updates are as easy as updating a Facebook page. The straightforward process means that a marketer has full transparency about campaign progress, full leeway on making decisions while the campaign is live, and, most importantly, full control.

The days of having full control over everything in the marketing mix — that was likely never the case and definitely isn't now.

But digital does empower marketers with tools to listen to customers and understand campaign results in real-time. The marketers who win are those who embrace an agile mindset and react by responding to customer needs.