There has been increasing buzz recently around 'headless' or 'decoupled' content management systems. In short, remove the presentational aspects of your content management system in favor of robust API support 1.
ALA On Air recently hosted a panel that spoke about this at length.
The key lesson for us was that a headless CMS helped solve a problem. We didn’t dive into headless CMSes because it was trendy, we did it because we needed to solve specific problems (in the first case an aesthetic/creative one, and in the second a data-management one). The other important outcome was that we could let each piece of the project do what it does best—by letting the CMS simply manage content, we could use better tools for rendering the presentation layer
Whats problems can we solve?
Performance: Let's take WordPress as an example. About one-fourth of content on the entire internet is managed and displayed using WordPress. It's no secret that the long lifespan and extensive feature set that comes alone comes at a pretty hefty price for performance.
While it may be just fine - and frankly, typically the right choice - to use WordPress' robust templating engine to display your content; other times you may want to simply provide a bit of data to a lightweight app or page.
Portability: If there's one thing API's were made for it's this.
Wordpress 4.4 will have WP-API as part of Core, Drupal has similar tools, heck - even Ghost provides an access API. ↩