The discussion revolves around the historical significance of the first C compiler source code from 1972, highlighting its unique features, such as its reliance on PDP-11 assembly code, and the nostalgia it evokes among early users of the language. Users reflect on the technical limitations of modern compilers, such as gcc, which cannot compile this early code, primarily due to obsolete assembly instructions and potential changes in the C language itself. The conversation also touches on the cultural legacy of C and its connection to early computing history, especially in academic settings like Harvard.