Essentially, this means devs can code apps for Chrome with the same tools they use to write native apps for a PC or mobile devices.
As Liliputing's Brad Linder notes, one of the most well known NaCI apps for Chrome is probably Nextflix, which allows users to stream videos on a Chromebook, even though the service typically only supports Mac and Windows computers.
However, up until recently, NaCI was only available for x86-powered devices. Fortunately, Google recently added support for ARM-based chips in Chrome OS 25, which means we are likely to see Netflix and other NaCI apps (Quake, Doom and NaClBox) running on ARM-powered devices like Samsung's Chromebook at some point in the very near future.
"While Chrome 25 and later will support NaCl on ARM-based devices, that only covers Chromebooks and PCs," Linder explained.
"The Google Chrome browser for Android doesn’t yet support any plugins or extensions, which means that you won’t be able to run games, video streaming services, or other NaCl apps in a Chrome browser on your Android phone or tablet yet."
It should be noted that Mountain View remains on track to publicly release its Portable Native Client at some point in 2013, which will allow devs to code an app once, while making sure it runs on any chip architecture, such as x86 and ARM.