As I understand, node.js is useful for Java Script programmers, who can now develop in server-side. Besides, some Java Script code can be ported from client-side to server-side.
Are there any other advantages for node.js in comparison with other server-side technologies (Java web frameworks, RoR, Django, etc.) ?
Package management
Compared to Java’s Maven node.js package management system(npm) is the best ever.
To me that alone should be enough to switch. The packages I recommend you to check out:
You can search for packages using http://search.npmjs.org/
Fast
node.js is very fast(event-loop non-blocking) and also has very speedy native bindings(C). For example node_redis(C binding) benchmarks:
Active development/community
Ryan Dahl is working very very hard on his project. Also node.js now has active support(sponsor) from for example Joyent. The community is growing rapidly