everal years ago, "content is king" became the battle cry of marketers everywhere. Content marketing has come a long way since then, shifting from the occasional on-the-side blog post and social media update to a central tenet of any brand's marketing playbook.

"Content is an integral part of marketing strategies all around," said Matthew Grant, director of content strategy for digital creative and marketing staffing firm Aquent. "[It is becoming] more and more difficult to distinguish content marketing from any other kind of marketing."

With the lines between marketing strategies continually blurring, what does the future of content marketing hold? Experts weighed in on the five biggest upcoming trends for this critical marketing strategy.