Node.js is still all the rage on the Web. But how is it actually being put to use? It's still in its early stages of development, so in many ways its dangerous for production use. None the less, a few companies are already using it. Kevin McCarthy talked to three companies - Yammer, Proxlet and Bocoup - about how each one is using Node.js. Sponsor Yammer - Yammer is using Node.js as a proxy for its API. Proxlet - Proxlet's Chrome plugin is built entirely in JavaScript and MongoDB.