A developer is defined as a computer programmer who creates software and drivers for specific platforms. The discussion highlights that a book like "Windows 7 for Developers" is aimed at individuals with a solid understanding of programming concepts and skills. It emphasizes that developer toolkits, such as those provided by Apple for iPhone app development, include essential resources like coding tools, debugging capabilities, and comprehensive guides. For Windows 7, the content would be more technical, covering system calls and the Windows kernel. Resources like the Microsoft Developer Network (MSDN) offer software and device driver kits necessary for development. The conversation also touches on the evolution of debugging methods, referencing older techniques that utilized serial ports for communication between systems.