You can embed external iframe, widgets, media player etc into superblog posts.
Just copy the external element (not the source code). Paste it into the post editor.
You should see a preview of the element. Once you click “Deploy” and visit the post URL, you can notice that the embedded content is visible and interactive.
examples
iframe: Iframe test | Sample Blog 6
podcast widget: Podcast widget test in the post | Sample Blog 1