Traditional application development usually involved coding a project and then physically testing it on a number of machines before the information technology specialists assigned to it felt that the software was good enough to ship. It then ended up either on physical media or in a repository somewhere. When users downloaded it, they had to install the program manually and then report any potential problems they had with it later on.

Modern SaaS application development follows a much different update path, which makes it far easier to keep current. Programmers usually develop a SaaS application...