When Joel wrote the test, there wasn't much development for the web; the little that was being done wasn't being done in any of the modern languages that we write in today. In fact, Facebook, Myspace, Twitter, Gmail, and LinkedIn hadn't even been invented yet. Today's world makes heavy use of web-based software (the term "software as as a service" keeps floating around). And so, it is necessary to update Joel's test in order to properly apply it to web development. This has been done by some folks, but I will do it again, mostly because I disagree with them.
The test asks questions about source control use, well-defined specifications, quiet working conditions, unit testing and bug fixing techniques. He works through each of these, sometimes just giving an update to the original discussion and others talking about how he disagrees with the concept all together (like having detailed specs).