This is a look at the print publishing business model. It is a simplified description, but understand the big picture is more important than the details.
Historically print publishers earned revenue from copy sales and advertising. Some publishers, mainly in the trade press, rely solely on advertising.
Others, such as book publishers, rely solely on copy sales. Most newspapers and magazines make money from a mix of the two. Historically newspapers published in the UK would make almost all their monty from copy sales. In the rest of the world advertising is more important.
The balance between advertising and copy sales revenue usually determines a title’s editorial strategy. One important part of this is that when the money comes mainly from readers, then serving their interests is unquestionable. When money mainly comes from advertisers there is always a temptation to pander to their needs over reader needs.
The revenue part of a publication’s business model is simple:
Revenue = copy sales + advertising sales
Publishers who rely mainly on copy sales for their income typically spend more on producing quality editorial to attract readers.
Advertising-focused publishers put less emphasis on editorial. In extreme cases, they do away with editorial all together producing publications which closely resemble catalogues.