What is Mass Marketing?

Legal Definition
Mass marketing is a market strategy in which a firm decides to ignore market segment differences and appeal the whole market with one offer or one strategy, which supports the idea of broadcasting a message that will reach the largest number of people possible. Traditionally mass marketing has focused on radio, television and newspapers as the media used to reach this broad audience. By reaching the largest audience possible, exposure to the product is maximized, and in theory this would directly correlate with a larger number of sales or buys into the product.

Mass marketing is the opposite of niche marketing, as it focuses on high sales and low prices and aims to provide products and services that will appeal to the whole market. Niche marketing targets a very specific segment of market; for example, specialized services or goods with few or no competitors.
-- Wikipedia
Legal Definition
Using mass distribution and mass media as a strategic attempt to reach an entire market with one basic, appealing marketing strategy. Also known as undifferentiated marketing.