Depends on what you mean by "still developing for Node.js" which is subjective. Going strictly off activity, the graphs on github[1][2] show node trending ever downward from a high back in early 2012, and iojs significantly spiking upward within the last few months, approaching 2012 levels. (Obviously all but the extreme right edge of both graphs share the same data.)
[1] https://github.com/joyent/node/graphs/contributors [2] https://github.com/iojs/io.js/graphs/contributors