This just gave me the idea of tagging tracebacks with the Python version number. Something like

Traceback (Py3.2.2, most recent call last):

and perhaps with the platform also

Traceback (most recent call last) [Py3.2.2 on win23]:

Since computation has stopped, the few extra milliseconds is trivial. This would certainly help on Python list and the tracker when people do post the traceback (which they do not always) without version and system (which they often do not, especially on Python list). It might suggest to people that this is important info to include. I wonder if this would also help with tracebacks sent to library/app developers.