A "longtail" refers to a statistical distribution where a large number of items have low demand, but collectively, they can make up a significant market share. This concept is often applied in various fields, including e-commerce, media, and search engines, where niche products or content can attract a dedicated audience over time. In the context of online retail, for example, while a few popular products may sell in high volumes, many less popular items can still generate substantial sales when combined. This allows businesses to cater to diverse customer preferences and maximize their overall revenue by offering a wide range of options.