Until about 10 years ago only Japanese knew about panko, but now not only celebrity chefs, but also people who are vaguely interested in cooking know about it.
As the image above shows, regular bread crumbs are darker, finer, and many are seasoned. On the other hand, panko is lighter in color, coarser, and unseasoned. Because flake size is larger, panko holds less oil than regular bread crumbs. It also gives crunchier texture to deep fried food, such as breaded shrimp fries, tonkatsu, chicken katsu, and breaded fried oysters.
It used to be difficult to find it in the United States, but now I see regular grocery stores carry several brand of them. You can also find them at Asian grocery stores and online.