"Until a few years ago, the topics in my Ph.D. were unfashionable, but they are very popular today"

Benoit Mandelbrot's quote is a reflection on the ever-changing nature of academic research study. He is suggesting that the topics he studied for his Ph.D. were not popular or trendy at the time, but have actually because become more extensively accepted and studied. This could be due to a range of aspects, such as the emergence of new innovations, the development of new theories, or the altering interests of the scholastic community. It is a tip that what is popular today may not be popular tomorrow, and that the subjects we study need to be selected thoroughly. It also functions as a pointer that we must be open to new ideas and research topics, as they may end up being popular in the future. Mandelbrot's quote is a testimony to the importance of staying up to date with the latest research study and trends in academic community.