As 2017 begins, CMOs and marketing executives across the country will reevaluate their strategies from 2016: what worked, what didn't, and what new ideas or technologies they should be on the lookout for this upcoming year.

I asked several digital marketing technology leaders to share their predictions for 2017.

Below, their responses:

Optimizely VP of Product Management Will Gradin

Marketers will need to implement machine learning

In 2017, machine learning will become a necessary component for marketers to meet business goals and objectives. Machine learning automatically makes personalized campaign changes on the fly, instantly altering how the customer is being targeted without the need for human intervention, or the risk of human error. Machine learning has the capability to uncover truths in patterns that humans might not be able to spot. It is going to be imperative that marketers incorporate these kinds of technologies in 2017.

Developers will also begin to leverage machine learning without having to build their own machine learning infrastructure by leveraging cloud services from companies such as Google and Microsoft. These cloud machine Machine Learning providers will soon eclipse former ML titans that pioneered the technology.

Campaign Monitor CMO Andrea Wildt

Email will stand alone as a content channel

Traditionally, email newsletters repurpose content from a brand's website or blog. This was a breakout year for email newsletters like The Skimm, proving that email has the potential deliver personalized content in a humanized style and tone, depending on the audience. In 2017, we expect to see more brands treating email as its own unique channel, especially with advanced features like integrated surveys and gifs. For example, BuzzFeed's email "challenges" send readers new fitness activities to remind them to change up their workouts every week. In light of issues such as Fake News, readers are also becoming more aware (and sometimes skeptical) of the sources they read, content from trusted sources will become even more important, and email ensures a direct connection from source to reader.

AdRoll President & CMO Adam Berke

Walled gardens won't come down, but doors will open

Although the walls surrounding data from major players like Facebook and Google won't be demolished in 2017, there are strong forces to incentivize them to work with the rest of the ecosystem. Marketers need data to flow between platforms to provide a holistic picture of their campaigns -- how customers are behaving and buying across channels as well as how solutions stack up against one another. As modern marketers continue to demand more transparency, in 2017 we'll see a bit of a pendulum swing back toward more openness as opposed to the trend of keeping data locked up in 2016. Facebook's partnership with Neustar is an example of what this might look like.

Segment CEO Peter Reinhardt

The collapse of small-time ad networks

In 2017, I think we will see the collapse of the smaller ad networks. There are two forces working against them- the continued dominance of Facebook and Google, and the widespread blocking of third-party cookies. As Facebook and Google continue to pull ahead in market share, the smaller networks are not able to compete. Last quarter, Facebook and Google each grew their ad revenues around 20 percent, while the combined remainder of the digital advertising ecosystem revenues shrunk to 5 percent. In 2017, we will see an acceleration of this trend - the small-time ad networks will no longer be relevant part of the larger ecosystem.

Also, the recent privacy development that Apple and Mozilla have taken to block third-party cookies will drastically hurt these smaller ad-networks. These networks are so dependent on third-party cookies for better targeting and to share data between services that they need these doors to be open in order to survive. Google is poised to deliver the final blow if/when it updates Chrome to follow suit on cookie privacy. This move will shut down the rest of the small-time ad-network ecosystem that relies on third party cookies.