Today the web browser get a more central role in the arsenal of programs users use and at the same time installing programs is a bit of the past and every type of applications gets a web alternative. Users sees this as a good thing, however software companies which have put a lot of time, effort and money into their products might not be as happy in this platform paradigm shift. The question is though, does it need to be a paradigm shift? Or is it possible to move an old application into this new, Operating System (OS) and architecture agnostic, multi purpose system the web has developed into? This thesis tries to summarize which techniques there are, how they work, what their strengths and weaknesses are. As a bonus it also contains an independent case study of how it is to use the technology Native Client (NaCl) in alarge scale project. The conclusion, from the case study, is that NaCl is a very promising technology both for migrating old code and for creating high performance code for this new platform. Our tests shows a 12:9% speed up when we using the 64 bitNaCl version over the native x86 32 bit version of Algodoo. However, even though the technology seems mature the Software Development Kit (SDK) aren't which might be reason enough to idle for a while.