In academic environments, we are often expected to support our points with evidence. Everyone has an opinion, but you are more likely to persuade others to see your side by using evidence. This evidence might be from your own experience or observation (e.g. you tried Internet dating and you enjoyed it) or from original research (e.g. you conducted a survey to find out how other people feel about internet dating), but more often this evidence will come from books, journal articles, and other published sources.