Again quoting a developerWorks explanation:
Barth talks more about how Development Seeds enjoys the elegance of being able to processing large chunks of data stream in real-time as soon as the first bytes of the data are received, and he talks about what the Express framework does and does not provide in the equivalent Drupal speak of terms and hook functions.
I also got a chance to talk with ZivTech's Justin Rendell at DrupalCon Chicago, who has written a Node.js Integration Drupal module in order to do real-time chatting a better experience with other modules like the Chat Room module. I'll be releasing that interview next week. UPDATE: Here's that interview with Justin Randell.
Interestingly, most of the development of node.js development is being coordinated through github, and since there's no centralized repository or issue queue, most features/bug fixes come in as pull requests on this GitHub repository: https://github.com/joyent/node/pulls
Node.js also just held a one-day NodeConf in Portland, OR, which over half of Development Seed attended. Barth talks about how node.js is still an emerging technology, but is really excited to see it mature over the next couple of years.