Timothy Pate

Amid accusations of Facebook suppressing conservative content in its “Trending” section, The New York Times examined social media’s evolving role as news source and curator.

For the companies, adding additional curated or original editorial content has an obvious appeal, helping them extract more value from people already using the platform, as well as potentially attracting new ones. “Each of these companies has to give people that aren’t coming there a reason to come there — new users, or infrequent users,” said Michael Pachter, an analyst for Wedbush Securities.

But, Mr. Pachter said, the presence of editorial operations risks emphasizing just how significant the companies have become as gatekeepers for news and entertainment.

“To edit it, and write it, and create it, and curate it, it’s a big responsibility,” he said. “I don’t think they realize what they’re getting into.”

That sites like Facebook and Twitter are becoming a primary source of news for many adults is not shocking any more. A 2015 survey by Pew Research found that a full 63 percent of people on both platforms said they got some of their news from the social media sites. But how that news arrives on our phones and computers has perhaps gone unquestioned for too long.

As acknowledged in the Times article, these sites will likely have to work hard to maintain trust as scrutiny of their methods ramps up.

“There are a lot of similarities between this situation and how little we knew about how traditional news organizations worked in the middle of the 20th century,” Ms. [Kjerstin] Thorson, said, “the last era before media trust plummeted.”

She added: “The question really is, how much sustained media attention to these processes will it require before these platforms must react in some way to preserve the trust they have?

“I suspect quite a bit.”