Friday Google announced a new RIA platform called Google Native Client (NaCl). NaCl provides a browser plug-in that allows your browser to run C/C++ applications directly on your x86 processor. Google is releasing it as open source (BSD-style license) very early in its development (“release early, release often!”).

Google NaCl is a fairly major departure in terms of architecture from many other RIA technologies. Silverlight, Flex, JavaFX, and Ajax all execute in a managed environment which is slower than native C/C++ code but is also more portable across operating systems and computer chip technologies. However, given the fact that the three most common desktop operating systems (Windows, Mac, and Linux) all run on the x86 chip architecture, portability across chip architectures would appear to be far less important today than it was five years ago. (Unless, of course, you also want your code to run on other devices such as smart phones.)

Even as a research project NaCl is both exciting and scary. It’s exciting because it promises much better performance, which means that graphic intensive games, 3D, and data visualizations have more potential than ever. It’s scary because it reminds us of ActiveX - one of the most unsecure technologies ever introduced to the Web. But is the ActiveX comparison fair? According to Google the NaCl employs very different security architecture. While ActiveX allows downloaded applications free rain over the operating system (an ActiveX control only needs your permission to install and it can do anything a native application can do), NaCl depends on existing “trusted” libraries to execute operations that might otherwise be exploitable by hackers. This early release of NaCl is specifically targeted at security professionals who are most likely to identify at least some security problems.

So if NaCl is as secure as Google says it is, and it offers native runtime performance, it would probably offer an excellent alternative to many other RIA technologies. That said its been demonstrated that performance is not a primary driver for developer adoption in the mass consumer space. What matters to developers of mass consumer RIA applications is ease of development. That means a development environment that is easy to use, a language that is easy to learn, lots of prefabricated components, and a thriving ecosystem. None of which is available for NaCl. The fact that NaCl applications are developed in C/C++ (not exactly the language of choice for most RIA developers and designers) is a huge obstacle to adoption. Not only is C/C++ unfamiliar to most RIA developers, its also a tricky platform (pointers anyone?) with a steep learning curve.

Of course Google’s NaCl is not the only choice you have for native, or near native, runtime performance. Curl (note: the author works for Curl) has based its architecture on native compilation for ten years and is portable accross Windows, Mac, and Linux. In addition, Google Chrome compiles JavaScript code to native code. Programming in JavaScript is far more enticing than C/C++.

As Google will soon discover, the performance advantage, while important in the enterprise, is of little marketing value in mass consumer applications. Most developers don’t think of raw performance until they hit a wall with their current RIA technology of choice and by then it’s probably very expensive to switch technology platforms.

There is another problem that promises to be a big barrier to adoption for NaCl in the mass consumer market. The NaCl runtime environment is a whopping 22MB in size. For the Mac the largest runtime environments for RIA technologies prior to NaCl were Java (15MB), Adobe AIR (12MB) and Curl (9MB). The plug-ins for Flex ( 5.5MB) and Silvelright 2 (7.1MB) are even smaller. Ajax is a mostly zero install technology.

While NaCl provides enticing performance advantages, there is no guarantee that NaCl will become competitive or even reach a final release. Other, better-established, players have already saturated the mass market and enterprise developers are less likely to adopt a technology that is called “experimental”. So while NaCl is interesting it is not a shoe-in as a game changer. Still, Google is a force to be reckoned with and NaCl cannot be dismissed easily.

Read more from Richard Monson-Haefel.