"All user experience, mobile or on the Web, in general is evented by nature – it's driven by the user touching something or taking some action," Prasad said. JavaScript and AJAX programming tend to be built around events for that nature, but many of the server-side languages for Web development such as PHP follow a more procedural model of doing things one at a time in a predefined order, he said, whereas Node.js makes server-side programming more like coding for the browser or a mobile client.

The Web and mobile development environments are converging around HTML5, he noted, adding that the LinkedIn iPhone app is actually "about 80% Web-based, and it's designed so you can't tell which parts are Web and which are native."

Another reason Node.js is making great performance gains is that it runs on the same V8 JavaScript Engine used in Google Chrome and therefore benefits from work that Google and other big companies are pouring into improving JavaScript performance on the browser.

The LinkedIn engineering group has taken to enthusiastically blogging about Node.js and how to maximize Node.js performance.

One of the biggest benefits is that JavaScript developers who previously were not comfortable with server-side programming now can work in both realms, Prasad said. "We don't really have client developers and server developers anymore --we just have developers." One reason LinkedIn is talking up the technology is it wants developers to know "if you're interested in this stuff, or you have experience with this stuff, you should come work here," he said.

Follow David F. Carr on Twitter @davidfcarr. The BrainYard is @thebyard

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