You might focus your argument on mass media in general or one specific form of media, such as cable news or newspapers.
Traditional mass media is produced and distributed by a select group of individuals working in the field. Consider how this affects what type of information is distributed and how people consume media.
To learn more about writing a compare and contrast essay, read: What causes people to act a certain way in public?
When was the last time you picked up a local newspaper? Newspaper readership has been on a steady decline for years.
Consider whether newspapers are relevant today or whether other forms of news are now more relevant.