I have very recently started development on a multiplayer browser game that will use nowjs to synchronize player states from the server state. I am new to server-side development (so many of the things I'm saying are probably being said incorrectly), and while I understand how node.js works on its own I have seen discussions about proxying HTTP requests through another server technology (a la NGinx or Apache) for efficiency.
I don't understand why it would be beneficial to do so, even though I've seen plenty of explanations of how to do so. My current plan is to have the game's website and info on the same server as the game itself, so if there is any gain from proxying node I'd love to know why.
When you say "through another technology" I assume you mean through a dedicated web server such as NGinx or Apache.
The reason you do that is b/c in a production environment there are a number of considerations you don't want your application to have to do on its own. Caching, domain (or sub-domain) mapping, perhaps security, SSL, load balancing, and serving static files to name a few.
The web servers are already built to do all those things for you, and so they can handle them and then pass only the requests on to your app that actually need to be handled by your app. They're also optimized for doing those things and will probably do them as well or better than the average developer can.
Hope that helps.