PlayPosit

I use video in different learning contexts, and sometimes I like to add questions and reflection time in to the video before I share it with my students.

There are a variety of programs that can help you to annotate (as it is called) on Youtube video (and other video streaming services). I've tried a few, and there are some really good platforms for this. The problem is that the students in most cases need to register before watching the video the teacher has annotated. But then I found PlayPosit

You can sign up for free, and then you can start annotating videos. You can insert a lot of question types in the video: multiple choice, open ended, reflections, etc. It's easy. You insert just the address to your Youtube or Vimeo in PlayPosit and you're off. Once you have made the additions you need, you can test it and then publish. You get a link that you can give your students (you even have a lot of advanced sharring features I haven't tried that yet). 

https://www.playposit.com