Article marketing is a method of advertising that has existed for pretty much as long as mass print media. The fundamental premise of articles to market is to advertise a service or product not by crafting a concise advertisement, but by writing a specific, beneficial article that is tangentially linked to the product or service under consideration.
So for example, to advertise articles for marketing, one might write an article about the purpose and history of article marketing. Or, less directly, a marketing article for a company selling flood protection and water damage services might be about historic or recently relevant floods.
The idea is that readers attracted to the article by way of interest or a need for information will then be informed about the business offering related services or products. All through history, such articles have showed up in virtually all kinds of printed media: pamphlets, brochures, magazines, and most frequently, news papers. Publishers in need of content are often willing to accept article marketing, which is given to them for free in exchange for the business' right to publish their contact data alongside the article.
Because the articles are more than mere adverts and actually consist of valuable information to entice readers, the publisher benefits from a growing readership, while the article writer benefits from extended awareness of their service or product. It is a proposition that is fundamentally advantageous to all parties engaged.
The advent of the internet revolutionized and extended the use of article marketing. The principle nonetheless continues to be largely unchanged: publishers - i.e. websites and blogs, as opposed to newspapers and magazines - accept articles from companies looking to indirectly promote their products as content for their web site. Given that a webpage is fairly cheap, if not entirely free based on the web space, companies are now furthermore able to support their own publishing efforts.
So for instance, a company might have its very own blog - or even dozens of blogs - to host the articles pointing towards their website. This is where article marketing starts to intersect with another popular factor of online advertising: search engine optimization. With search engine optimization, an internet site through which a client dreams to sell a product or service hires a company (or someone internally to do it for them) to write articles that are once again tangentially connected to the service or product being presented. The articles are then hosted on different blogs or websites.
The difference is that in said articles, hyperlinks of key words are placed leading back to the client's website, and the articles that are created are almost never, if ever, even read by actual human readers. As an alternative, when a person searches for the keyword (to reuse the above example: flood protection) in a search engine such as Google, the search engine encounters the hyperlinks with that key word pointing towards that website, and then returns the website in the search at a better ranking, as more related.