You can have lots of historical fun by looking at the definition of “news” over time. Entrepreneurs quickly figured out that people would pay to get information faster. The quality of the information counted, but assuming that the facts were accurate, sooner meant money, especially to businesses.
They started with fast ships. Signal telegraphs - mechanical, not electrical - came next, which accounts for the rash of newspapers called Daily Telegraph in the 1820s and 1830s. The electrical telegraph changed everything. But it had gaps. Reuters started out as a homing pigeon service to breach one such in Europe.
The advent of giant mechanical presses allowed papers to put out multiple editions every day. Some got up to a dozen, with those iconic newsboys calling out Extra (sometimes spelled Extra) to passers-by in crowded downtowns.
So there’s always been an emphasis on the new in news as opposed to the mere informational value of information. Breaking news is a relatively recent term. It doesn’t get popular until the 1960s. That means television, of course. Although radio had some newscasts, especially during WWII, the regular evening telecast as a cultural institution is from television. Some news, the most urgent dire news, justified breaking into regularly scheduled programming. The Kennedy assassination is foremost, though not first.
So breaking news came from breaking into programming. As news expanded from a 15-minute national program to a half-hour of national and an hour or two or even three of local news, then a sizable portion of the day was news rather than entertainment. Breaking news became news that became available during a news program.
And then CNN. News all day, twenty-hours a day. Except that any regular viewer quickly realized that the same news was repeated over and over again with each hour, and every half-hour when the Headline News channel debuted. Breaking into news programming still happened but real news too important to wait for the next hour was still rare.
My impression from watching a lot of CNN for coverage of Japan is that they use Breaking News in a couple of overlapping ways. One is that new information relevant to the ongoing story is available and the other is that here’s more of that big ongoing story that you’re tuning in for. The latter is often not “new” or previously unreported. But people tend to watch channels like CNN off and on over the day, or keep it in the background and pay attention at intervals. Why alienate them by limiting breaking news to the first few minutes? If it’s likely to be new since the last time they paid attention, even if that was hours ago, it’s still new information to them.
If the meaning has changed from literal to marketing-speak, and I think it has, it still retains some value as a device that cues viewers that something has happened that worth their attention. Any capital N News will still override anything else. The broadcast networks can still break into programs and have true Breaking News. But the term has lost most of its meaning in a world of instant communication and constant access.