It doesn't really matter if you are writing informational articles, product reviews, or editorials, you always are writing to someone. The trick is determining who that someone is.
Your target market is actually not one person, but a demographic. It may actually be more than one demographic.
For instance, in my brick and mortar store, my target demographic is different than my target demographic for my online website for the same store. My walk in customers range in age from about 25 to 75, are 75% white, and 80% female. They have full time jobs, and are almost always married or in a committed relationship. Online the demographic is similar, but younger, (older people do not shop online as much), and and most are former Clevelanders, or Ohioans that are too far to drive to the store.
You will always have outlying people from your normal target market. However, in order to be successful, you need to focus your attention on the main part of your target market, and ignore the rest. They will come in as a matter of course.
To determine who your target market is, do some market research. Are you part of that market? Do you know people who are? Where do they hang out? Where is the best place to find them? What do they like and dislike? What other interests do they have? By doing some research, you will find places to promote or possibly cross promote with other writer, websites, or offline activities.