Companies, for online promotion of their products, follow different types of marketing strategies. Marking products through articles submitted to (published by) article directories is also considered as a standard marketing strategy.
There are two primary advantages of article marketing, link building and making your company publically popular. Links are very important for search engine positions. The article byline or footer help you to include some promotional info about your company or product or service. Article marketing really work when you are marketing your products globally, and for companies who deal with less popular products/services. Just providing readers about the advantages of the product you are offering and then the information where they can find it, is a really good marketing tactics.
The basic skill needed for article marketing is the writing skill, one have to write interesting and informatively. You can outsource this work to some low cost freelance writers in different parts of the world. Article marketing is now established as a large industry with many firms in it for profit.