//Twitter is the hub of all news. It's live streamed from the scenes usually so then news outlets get their information from here. That, or they have twitter teams on the ground. //
That's supposed to be what wire services are for. Of course, the habit of "journalists" to simply copy-paste whatever they get/buy from wire services without checking it is well-documented and entirely a product of the "24-7" news cycle we currently live in. People demand coverage - any coverage - so quickly that it is impossible to properly verify, or often to properly investigate. News organisations frequently have to choose between doing investigative reporting (still happens sometimes, though usually seems to be when stuff is brought to them) or ill-verified 24-7 news coverage. Alas, they usually choose the latter.
With some exceptions (e.g. the current President's tendency to contradict his own government on twitter, or the early days of the Arab Spring), Twitter is very very rarely "the story." It's just there to make up space and pad out an article.