I am using the new Cascade builder. Is it possible to expand the template with the ability to add Youtube movies?
You can already add YouTube (or Vimeo) videos to your Cascade stories; just paste the URL of the video in the Link to Content tab.
Also, here's a blog post about all the features of the Cascade Media Picker:
Using the Story Map Cascade Builder: Media Picker | ArcGIS Blog
Owen,Thanks for your post. I was using the wrong URL, after reading the blog post everything went well,