Whoa, who said anything about full stack replacement. I use a variety of stacks, I was simply pointing out that since I'm using Javascript all over the place anyway, I might start using it on the server side as well. Things I use Ruby for generally amount to one-off jobs or shell-scripts. I constantly have to remind myself of the syntax, since all I use all day long are variants of C syntax(C#, java, javascript). It'll take me 10 minutes to whip up what would take me 30 in ruby, simply because I don't use ruby often enough to internalize the syntax. node provides me with a way to write the same shell scripts in javascript.