There are two main reasons that people write articles online. One reason is to spread the word about a cause, issue, or facts. The second reason is to earn money through clicks or sales. Sometimes you can do both with the same page.
One of the key factors we look for when assessing whether an article is successful at achieving its purpose is the traffic it attracts. This can be measured by analytical statistics which track visitors' behavior on websites. However, traffic alone is not a good measure of an article's success. It is way more important that your article is reaching the people that you are trying to reach, and that those people are interacting with the article in the way you want them to. In the case of an sales article, that interaction would be actual purchases (sales conversions).