I created a simple plane and sphere in unity and added the mouse orbit script to the camera to add some functionality. Then I exported using default web player settings and uploaded both the .html and .unity3d files to a public folder on Dropbox
I tried many ways of embedding onto Blogger, but in the end found that this link:
[there is an updated iframe gadget url in the comments]
Using the HTML code in Blogger, I added the code:
<iframe height="440" name="Test" src="http://www.gayasoft.ch/bloggergadget/UnityIFrameGadget.php?url=http://dl.dropboxusercontent.com/u/2515267/Builds.unity3d&width=560&height=420" width="590">...</iframe>
Worth noting from the blog post is I needed to add a "<" before the iframe and a "</iframe>" to close the code. Also when pointing to a Dropbox url you need to change the "https://" to "http://" to allow a public link regardless of it being in a public folder.
Finally if you want to have text in a blog post with the embedded webplayer, you need to surround the webplayer code with a body (<body></body>)
Finally if you want to have text in a blog post with the embedded webplayer, you need to surround the webplayer code with a body (<body></body>)