If you want to display a video on your web page or blog, you can embed a video you already hosted at YouTube. This is relatively easy to do, but there are a couple of settings to pay attention to.
After you've found your video on YouTube, you need to copy the embed code.
Return to your website or blog and look for an HTML button. This will change the look of your page...don't panic! Paste the embed code and then click HTML again (or Compose if using Blogger) to return to the previous screen.
I have used this technique because the server that hosts my school's webpage does not like hosting videos (uploading them there takes up too much space). I can embed a video there that I have hosted somewhere else instead.
Also, if you want students to watch a video from another site such as YouTube, embedding that video on your site or blog is a way to allow students to see the video without all of the extra clutter that comes along on the origin's website.