It's been going on for a long time, but now seems to be getting worse. Fox News Channel started it and continues to use it: "Breaking News" flags with heavy music blast to emphasize its importance. The use of "Breaking News" is now used by regular television broadcast stations.
News does break. But, once it breaks, it is broken and is a continuing story. It doesn't become "breaking news" over and over again throughout the day.
As an example, a local television station on its morning news program show displays --- and the reporter says --- "breaking news" and presents the story, and continues to repeat the same story and identify it as breaking news an hour and two hours later.
This is a blatant example of how to try to magnify, or accentuate the presentation to create the impression that is fresh, previously unknown and of great importance when the story is not. It makes it appear their reporters and staff are working feverishly to develop the story when, in reality, they are doing nothing but making a phone call or visit to the scene or authority source at a later time to see if there are any updates.
The use of "breaking news" statement is also used to emphasize the more newness of the report as compared to the other recorded stories that have been repeated for at least 24 hours through several news programs before dropping off the revolving production table.
An update to a story is not "breaking news," but rather an update.
The "Breaking News" is so over-used now that it gets passed off by many viewers. It is a self-promotion gimmick, just like when news "reporters" give live or pre-recorded reports that claim "exclusive to our channel" as part of the rhetoric to present the story.
Some day someone who is really responsible and dedicated to presenting the full and truthful story of an incident, without any opinions or conjectures, will really present facts without the use of the audio-visual gimmicks and I, as a viewer, will appreciate and recognize it as an honest news report.
So, when you see a television channel use the comments or visuals that say "Breaking News" about the same story several times, or says the story is exclusive, have a good laugh, because they're just trying to impress you by patting themselves on the back. Those terms mean nothing.