I have a theory about this. It has to do with the fact that Fogbugz started as off-the-shelf software, where companies would buy the CD and install the software on their own servers. The hosted version came much later.
Considering that most of the original code base was using ASP (there was no .NET when they started), this meant that all of their source code had to be shipped with the product. They couldn't just ship binaries. So part of me wonders if the Wasabi idea was a way for them to have obfuscation and some protection against piracy and competitor knock-offs.
I'm pretty sure it had more to do with supporting Windows and Linux server installs. I know we looked at FogBugz for an internal use, but at the time it was Windows only. Since we were a Linux shop, there was no way it was going to work.
I don't know... if Linux support was their only goal, there were other options that could be taken into consideration. I'm reasonably sure that around 2005 there were some solutions that made it possible to run ASP on Apache. At the time, even Mono/XSP was somewhat viable. [1]
Wasabi nowadays uses Mono, and until very recently, whether it was legitimately viable was a matter of opinion. Technically speaking, its garbage collector made it ill-suited to long-running processes (such as web servers), and its performance was far worse than the Microsoft CLR--frequently two to five times slower. Ideologically, we also met resistance; many Linux system administrators seem far more reticent to install Mono compared to PHP. Both have improved recently, but back in 2005, Mono was not a sane option.
Yeah, but I wouldn't have installed that on my server, it would have been too awkward and a support challenge for FogCreek. So, I think the idea was to support deployment on a standard runtime for each platform: PHP on Linux, ASP on Windows.
Considering that most of the original code base was using ASP (there was no .NET when they started), this meant that all of their source code had to be shipped with the product. They couldn't just ship binaries. So part of me wonders if the Wasabi idea was a way for them to have obfuscation and some protection against piracy and competitor knock-offs.