The New York Times addresses an interesting question with regard to news staying “fresh”.
With such saturation coverage, news gets used up faster, decaying rapidly into what Russell Baker calls “the olds.” Public curiosity, let alone the public interest, is exhausted, and the mass media are quick to look for some new sensation even if that means leaving important issues unresolved.
They may be on to something. However, the opposite can also be observed as some stories, of relatively trivial nature, can get stuck in the cycle long after their usefulness as news has expired (i.e. Condit/Levy, Britney’s marriage, etc.)