You decide what you are going to write about. One day it might be about this great new program you have come across. So you write your own article on it. I did say article not Ad. There is a big difference.
Most people read Articles.
It can be great fun. When you start getting the feedback e mails. Some of the comments can be great fun and lift your heart to new heights. These sites will give you ideas on what to write about etc. With your questions we will try and answer them.