Flutter, a startup offering free software that allows you to control music and videos on a computer with simple hand gestures, is adding to its repertoire of gestural tricks. The San Francisco-based company is rolling out the ability technology can control content on the Web, too.

The new software, available Friday as an extension for Google’s Chrome browser, lets users play, pause, and skip videos on YouTube and Netflix and tunes on Grooveshark and Pandora.

Gesture controls have been on the rise over the last few years, helped in part by the success of Microsoft’s Kinect motion sensor, which made it possible to control the Xbox with your body. Devices like a Samsung TV with gesture-control technology have also helped push it into the spotlight. But unlike other current gesture-control software, which requires dedicated hardware or only works on some gadgets, Flutter works with just a webcam—such as the ones built into millions of laptops, smartphones, and tablets.

Flutter rolled out its first product in March (see “Hold Your Hand Up to Play Some Music”) and already offers desktop software for Macs and PCs that lets users pause or play music and videos by holding up an open palm, or skip songs by holding a thumb to the right or left. The software is compatible with applications including iTunes, Spotify, and Windows Media Player. Since launch, Flutter has gained over 500,000 users and tracked about 26 million gestures, founders Mehul Nariyawala and Navneet Dalal say.

Now Flutter’s founders hope the new capabilities will rope in more users. When you use the Chrome plug-in, a thumb held out to the right or left will skip to the next video on YouTube (if you’ve compiled a playlist) or to the next chapter in a movie you’re watching on Netflix. Eventually, the company plans to enable standard fast-forwarding and rewinding within a video, too.

Flutter’s Chrome extension connects with the Flutter desktop application, which continuously processes images captured by your computer’s webcam. The software looks for specific gestures, such as a palm held up flat to signify play or pause. It then extracts the shape of your hand, determines what command you’re trying to communicate, and, if you’re using the extension, sends this command to the browser to control the website you’re using.

Dalal and Nariyawala say they plan to add support for additional websites, such as Hulu, which they expect to be available in January. “Once we figure out the right use cases, we’ll keep expanding it,” Dalal says.

On Friday the company also announced an update that enables its desktop software to control QuickTime, PowerPoint, and Keynote applications.

And Flutter’s founders say the company is planning still more capabilities: volume up and down gestures, a finger-to-the-lips gesture for muting, and a thumbs-up gesture to “like” songs will be introduced in January or February. The company is determining whether to add a thumbs-down icon, but the action may be deemed too awkward.

Mobile apps are in the works as well—Dalal and Nariyawala showed me a demo of their gesture recognition on an iPhone, and they’re hoping to have something out within the first half of the year.

Flutter has yet to reveal a plan for turning these cool tricks into a profitable business. But sometime next year, Nariyawala expects, the company will turn to a “freemium” model where certain features are free and others must be paid for. He and Dalal also believe they can make money by charging other developers to use their technology in their own apps.