FORTUNE — For a minute there in 2012 it seemed like the whole world might learn to code online, for free. It’s easy (or so we were told): Just use one of the zillion new learn-to-code services that had cropped up, seemingly overnight. They varied in quality, cost, and coverage, but one making a lot of noise was Codecademy. The New York startup raised $12.5 million in venture funding and boasted high profile partnerships with colleges such as NYU, government groups such as the White House, and tech companies such as Twitter. Even Mayor Bloomberg signed up for lessons.
And then the MOOC backlash happened. MOOCs, or massive open online learning courses, like those offered by Coursera and the Khan Academy, were quickly labeled condescendingly as “Internet college” and dismissed for their insanely low completion rates. (Less than 13% of people actually complete online courses.) Turned out disrupting Big Education wouldn’t be as easy as throwing up a website and some video lectures.
Codecademy has been quiet for the past year. It has revamped its product to distance itself from MOOCs, looking to offer tools that suit the way people want to learn online. The problem with MOOCs, according to Codecademy founder Zach Sims, is that they simply try to replicate the offline learning experience. The web presents the opportunity to learn in an entirely new way, he says. Over the last year, the company has been tweaking its offerings to better reflect the way people want to learn programming.
Codecademy’s redesign includes more interactive learning environments — allowing users to experiment with code in the browser — along with hands-on projects, and easy ways to save and share your work with others.
But perhaps more importantly, the company revealed that its efforts have actually been working: To date, 24 million people have used Codecademy. Of those, 5.5 million are registered users. (Users don’t have to create an account in order to take a course.) They’ve created 100,000 different courses and written more than a billion lines of code.
Rather than track how many have gone from zero to coding genius, the company has seen a “drop-in, drop-out” pattern of activity on its site. Users don’t sit down for an hour-long lecture; instead they learn skills in bite-sized pieces. It goes back to the web-centric way of learning, which Sims calls “chunked learning.”
Indeed, many of the site’s most popular courses are completed by skilled workers who need to learn a specific integration, or script. (The company partners with consumer tech companies such as Twitter, Evernote, and Box to offer courses on their APIs.)
Soon, Codecademy will introduce monetization by connecting programmers to employers eager to hire technical talent, Sims says. That could pose a geographical challenge, given that 70% of Codecademy’s users are from outside of the US. For example, the company has partnered with the U.K. government to use Codecademy in many of its schools.