Sensationalism is a manner of being extremely controversial, loud, or attention-grabbing. It is especially applied to the emphasis of the unusual or atypical. It is also a form of theatre.
The term is commonly used in reference to the media. Critics of media bias of all political stripes often charge the media with engaging in sensationalism in their reporting and conduct. That is, the notion that media outlets often choose to report heavily on stories with shock value or attention-grabbing names or events, rather than reporting on more pressing issues to the general public.