Went to a developers meetup last night that covered RethinkDB and Grunt.

RethinkDB is a NoSQL database with a query syntax that reminds me of jQuery, lots of chained selectors. The primary application seems to be highly reponsive real-time apps, where its push notifications provide a simpler and more scalable alternative to having to poll the database every few seconds. It might be useful for a future project but I won't be using it for WSN because of the impracticality of helping everyone to install it on their servers. Really the only components where it'd be notably better than MySQL are the chat and IM systems.

Grunt looks much more useful for my development process. It's a task automation tool with 5000 different task plugins, especially useful for the build and release process. I've already built a suite of custom automation and release tools for WSN, but I'll be incorproating Grunt into those in the future to leverage all the plugins.