Well, I have a big long list of the issues that were present in that movie. First, the file of the investigator's desk. The question she was faced with was private information vs. the public's right to know. She chose the public's right to know.
Another issue was when Gallagher asked Megan who her source was for the story. Should she keep it hidden, or does the "victim" have the right to know who is saying those things about him? She kept her source secret until much later in the movie. The question is, was that fair? Especially because she got the information through snooping.
Next, recording their conversation on the boat without him knowing. It is legal in some places and not in others. But legal and ethical are two different things. Right along those lines, when he found out about the tape recorder, she had to make a choice to write the story or not. And she didn't. At least from that conversation.
One of the biggest issues in this movie is when she talks to Teresa about the abortion. Teresa didn't specifically ask her not to write the story, although she asked her to leave the specific details out of it. She had a choice to grant that request or to ignore it and print it anyway. She had to decide what was more important; the source's privacy, or all the facts in print. She chose to print all the facts.
For some of us, these issues are "duh" questions. We look at it and say, "she should never have done that.", or "she should have done that" depending on what it was. But it's always easier from the outside looking in. When you're in the situation, sometimes it is hard to know what is right. Because the public DOES have a right to know; she just didn't think about how much, and at what cost.
I personally would not have read the file off of the desk. I wouldn't have printed all the details about Teresa's story. I wouldn't have done a lot of the things that Megan did in that movie. But that's just me. It doesn't necessarily make me right. That's why it's the gray area.