Because our service, Filer.io, currently supports Rails. However, Node.js support is coming really soon and Node projects will be welcome in the next contest.
"I certainly don’t mind a search engine using my previous search history to help me find better content."
I actually do. This, in fact, is a form of control over the information you get. Since I do not like that, I stick with DDG despite all the inconveniences.
Google should give people a way to opt out of the bubble.
[1] http://en.wikipedia.org/wiki/Monit