To take advantage of the affiliate programs that are currently available, you can earn money and also learn and improve your marketing skills. Remember, you can always earn money recommending products related to your topics of interest, that you will feel comfortable; but you can also venture to promote products and services of totally unknown areas but with great demand in the market. What sell, how to sell it and where? Big business is mainly to promote digital products and services. But what is it? Do you mean with digital? Similar to a service is intangible, a digital item is also; and this can be an e-book with relevant information to certain people, a cookery course in downloadable video to your computer, a training for pets in audio and video guide, an auto program helps to combat phobias, etc. A digital product is all information that comes in the format of text, audio and video that can be downloaded to any computer anywhere in the world and that can be marketed easily. And sales of digital products through affiliate marketing have many advantages including is that from the beginning and never exist physical inventories, no salaries, no investment initial (only need to invest in tools and infrastructure), and release an exaggerated load of time to spend on what you most like you do. There are several web sites where thousands of people congregate to market their products or services online, are like virtual markets and flows of products and operations of purchase sale carried out are huge day after day. Web sites such as Clickbank and Payspree, are specialized sites are mercadean where such products as: software, courses, ebooks, multimedia information, etc and have a huge stock of products properly classified under different categories and themes with very high demand around the world. They also have an arsenal of tools to facilitate both sellers and promoters operations or affiliates.