One thing that I think about sometimes is the similarity between journalism and insider trading. Consider: You are in the business of finding out things about companies that nobody else knows, so you spend your time developing sources at those companies who will tell you things. If their company has a new product coming out, or is about to announce a merger, or has been doing fraud, they call you to tell you before anyone else knows.

Sometimes they tell you things just because you ask, and they are indiscreet. Sometimes they tell you things out of a sense of public-spiritedness: They think that what they know should be known more broadly. Sometimes they tell you things out of a sense of grievance: They are mad at their bosses and want to leak information. Sometimes they tell you things because you are friends: You have done such a good job of developing relationships that your sources think of you as a personal friend, not just a transactional counterparty. Sometimes there is some amount of favor-trading involved: You get information from them, and in exchange you give them something that they want. Perhaps that is also information: You give them news or gossip about their firm or industry that you got from other sources. Or perhaps you can give them career advice. Or maybe you just buy them lunch, or drinks. Maybe you pay them cash! Often, of course, their motives are mixed; they tell you stuff out of public-spiritedness and grievance and friendship and favor-trading and carelessness all at once.