This question is prompted by some comments made over at http://drupal.org/comment/reply/13129/21713.

I'm not familiar with Plone at all. In fact, I couldn't even tell you what Python code looked like if I saw it. Zope sounds like a dark force ready to suck me into another universe. But its technological intimidation factor aside, it is the mother of all CMS software, at least from what little I've read and heard. Given that it even has some of code written in C for performance purposes, I can only assume that Plone is an industrial, heavy-duty CMS system.

I'm just wondering what Drupal's niche in the CMS software ecology is compared to Plone. What advantages does Drupal have? Disadvantages? Does Drupal aspire to evolve into a better, stronger version of Plone or is there something inherent about Drupal's architecture that would prevent that from ever happening? And what really distinguishes the two programs? Are there some things one is good at that the other is not?