To make it easier to reproduce the results of a given notebook, especially after a significant amount of time has passed, it might be nice to automatically include some information about the environment at the time of the notebook creation.

Basic things that would be useful to include:

• OS/architecture
• Python version
• IPython version

Additionally, each time a library is imported, it's __version__ could be pulled and a list of libraries + versions could also be included.

I would imagine that many people who are using and sharing IPython notebooks are interested in making their results as easily reproducible as possible, but if it turns out that many users do not wish to have this information automatically included, perhaps configuration setting could be provided to disable this option.

I'm sure there are even more things you could imagine including (e.g. GCC availability/version), but I think these things would already go a long way.