News organizations do two major things, commercially speaking: they use news to grab attention and then sell that attention to advertisers.
In the old chain of news production, a piece of timely information was researched by journalists, sifted through by publishers, and disseminated. It was a reporting of the facts rather than an expression of opinion.
As traditional news organizations faced the maelstrom of the digital revolution, many noticed that it was not just the stuff that editors had deemed socially important that was drawing in readers. Tailored, specialized news — the style and sport sections — that appeal to specific demographics pulled attention and therefore advertiser interest. Some hypothesized that tailored content could go further. Local newspapers, for example, could provide hyper-local content of interest to neighborhoods, like newsletters but with ads.
Facebook is what became of the "hyper-local" notion. It just turned out that it wasn't a geographic neighborhood but a socially connected one. Facebook provided a platform whereby individuals became reporters, editors, and publishers.
In this regard, Facebook is delivering on the first task of the news organization. Some Facebook friends might express opinions, but more often they are reporting facts. What is more, because these facts are reported to social connections, they are actually accurate. Nothing binds one to the truth more than the accountability of an ongoing personal relationship. Do you ever hear it exclaimed, "I heard on Facebook that your train broke down and that turned out to be an exaggeration"?