If so, yes, that's what a saved ipython notebook is. See: http://ipython.org/notebook.html for an overview of ipython notebooks.
You can export it to html, latex, etc using "ipython nbconvert --to <format_you_want>". See: http://ipython.org/ipython-doc/dev/interactive/notebook.html...
Basically, the website you're seeing (nbviewer) hosts ipython notebooks (json files) and converts them to static html for viewing.