If you are thinking about using node.js for this reason[1] on most sites, you are optimizing poorly. LinkedIn didn't worry about this until after they were a public company. If Python/Djando or Ruby/Rails can get your app out the door and into customer hands faster, it is almost always the right thing to use. 1. There are certainly other, very valid, technical reasons for choosing node.js over other technologies earl…
I'm sure LinkedIn could have cut servers without switching to node. Take your first, crappy implementation and rewrite it in the same language and you'll probably still see at least 10x improvement, if not 20.
This is hardly surprising.