In light of allegations that Russian interests utilized FB advertisements and other elements of the FB platform to promote "fake news" and influence the outcome of the 2016 election, have Facebook or Zuckerberg ever suggested that people should seek alternatives to Facebook in seeking/ verifying news?
While not an outright recommendation to seek verification elsewhere, there is an implied suggestion to do so in the 18 November 2016 post by Zuckerberg concerning Facebook's approach to misinformation/"fake news"..
Specifically, that post mentions Snopes as a resource for verifying the veracity of a story, combined with acknowledging that they will act on reports of misinformation:
we use signals from those reports along with a number of others -- like people sharing links to myth-busting sites such as Snopes -- to understand which stories we can confidently classify as misinformation
The post also contains an even more vague statement about seeking out third party fact-checking, which could be read as a recommendation for the users to do the same; however, it could alternatively be read as telling users that Facebook will handle finding those fact-checking organizations for them and now action is needed on the users part.
Third party verification. There are many respected fact checking organizations and, while we have reached out to some, we plan to learn from many more.
Overall, it's not strong advice towards users doing more independent research, though I think it would be a stretch to say that Facebook actively discourages seeking alternative sources.
Not as far as I can find. Let's take the important passage from the Zuckerberg statement that LazyGadfly linked to, which is about the only sort of official statement that has come out of FB:
The problems here are complex, both technically and philosophically. We believe in giving people a voice, which means erring on the side of letting people share what they want whenever possible. We need to be careful not to discourage sharing of opinions or to mistakenly restrict accurate content. We do not want to be arbiters of truth ourselves, but instead rely on our community and trusted third parties.
The problem isn't opinion, it's misinformation being palmed off as 'fact'. This guy is still talking like FB is just a simple discussion group. Hint: discussion groups don't put together pages that look exactly like a news site, and bill those pages as a 'news feed'.
Keep in mind that FB is not an accredited news source, with real reporters, real editors, and definitely not real fact checkers. Granted, the majority of the accredited news agencies can be challenged in the objectivity department, but they are held to some standards of journalism.
And, yes, news agencies are expected, both legally and ethically, to be if not arbiters of truth, definitely arbiters of fact. That includes validating sources, and filtering out news stories that are not factual. Clever of Zuckerberg to use the word 'truth' instead of 'fact'.
Based on Zuck's statement, it appears that he isn't even publicly acknowledging the problem or FB's position as an unofficial 'news source'. Summary of his statement on accuracy: we don't do any fact checking or validation of sources, other than what some of our members might report.
So Zuck has yet to face the issue that he rakes in the profit from acting like a news agency, while openly abdicating the responsibility that comes with that position.
The effect of the Russian efforts on the 2016 election are debatable. However, the deeper alarm is how FB itself propagates dubious news, and profits from that propagation, while coyly insisting that they're just a discussion group that doesn't want to 'censor its members'.
It is ironic that much of the public turned away from mainstream media, possibly because of the obvious slants in reporting and hyping to generate ad revenue going on today, only to get something far worse.
We started making changes in this direction last year, but it will take months for this new focus to make its way through all our products. The first changes you'll see will be in News Feed, where you can expect to see more from your friends, family and groups.
As we roll this out, you'll see less public content like posts from businesses, brands, and media. And the public content you see more will be held to the same standard -- it should encourage meaningful interactions between people.
This has been widely interpreted (e.g. Recode) as Facebook deemphasizing news and reemphasizing interpersonal connections. So even if people want to get their news from Facebook, they will be less able to do so.