OK, I’m going to show my age…a couple of decades ago, the public relations profession was in trouble and thoroughly misunderstood. As a profession, it lacked luster. So, the pros (me among them, though I was a cub then:) worked on a national public relations campaign for public relations. It worked. Public relations became recognized as a true profession, though there were and still are nitwits that don’t get it.

Notice that I avoided putting a specific dollar figure on the amount you can make from blogging. It will come down to your work ethic, your skills as a writer, your ability to generate targeted traffic, and plain old good luck. It’s a bit like baseball: everyone played it as a kid, only a small fraction make it to college ball, an even smaller number become professional, but only the cream of the crop makes it to the majors.
Once you setup your account on AdSense you will be given a code to add to your blog. This code will automatically display advertisements on your blog from companies who are part of Google’s advertising network. You may see ads from small companies related to your topic, or you may see ads from large companies that are completely unrelated to your topic.