The IPython dev team gets a lot of questions about how IPython Notebooks can be used on various blogging platforms. There have been a number of different attempts to use nbconvert to export a notebook to HTML and then embedding that HTML in the blogging platform. With the introduction of nbviewer it is trivial to embed a Notebook in any web page using iframes. Here is a simple example:
Which produces the embedded Notebook shown below. The only subtle part is that you have to set the width and height attributes manually to avoid having scroll bars on the iframe.