This is not as simple as it looks.
I think it would be better to provide a way to note that a claim is contested. It is just not clear in many cases what the facts are.
To add value to this, you could tell people what things the various parties think are facts. People might be interest to hear that the site says Elvis is still alive, the earth is flat, that evolution is a communist lie,
that this commentator said in 2007 there was a 'zero' chance of a major housing downturn in our lifetime, that this site said that Trump had no chance to win in 2016, that (6 months ago) the Muller report is going to be coming out within a few days, etc.
Other useful information: Who owns, sponsors, pays for lots of advertisements etc on that site? Where would you position them ideologically? Do they admit errors and publish retractions?
Trump has a good chance to win the 2016 election.
Fact check: False! The NYT says Clinton has > 98% chance to win!
I would stress how the claim is contested and by whom. I'd love to see a credibility network distribute this problem across its users, but I know there will be unforeseen problems. For example dissenter.com currently has a comment on itself that 'The sanitization of internet is a crime against humanity...' I sincerely hope this is satire, because it's well known that comment sections can be unsanitary.
I have heard of similar attempts, for example, Media Bias/Fact Check (dot com) has some browser extensions, which purport to show the political bias of known sources. The website also claims to rate news organizations on factual accuracy.
That said, consuming even "honest" news sources will give you a very distorted picture of reality, due to the way the news tends to prey on human bias. Because of this, mere fact checking doesn't go nearly far enough: outliers need to be put in perspective.
You haven't made a proposal of how the system would work theoretically, so we aren't even at the problem that needs software developers.
You didn't say who's supposed to spent the time to do to link to all the fact-checking websites and make the decision about how what's written in the article corresponds to what's written on the fact checking websites.
Just had this idea, writing while I'm excited about it -
We all know the problem of fake new, of too much information to be checked - and that most people don't know how to do that, don't want to, or just don't have the time or energy.
And i can't blame them, it is hard. it's not like i fact-check everything i read.
so here's what i would like to see -
An embedded widget for news-sites, that automatically curates fact checking from many/all fact-checking websites. this is not a website or a browser extension that does it, but server-side. so everyone reading the article would see the fact checking results, and also see whether there's a consensus or a disagreement between the fact-checkers.
This will make people think critically about the things they read, and journalists at major news organizations would think twice before publishing.
And this isn't useful only for news outlets - this can also be used by social media (YouTube, Facebook, Twitter, Reddit). If a post had any fact checking made on it, it'll have a small icon, which brings up a popup with the widget once clicked. truly, it can be used in any place which wants it's audience to think critically.
It can be done using a URL based approach, like the new dissenter extension. but how it is developed matters less, so i won't elaborate on that.
the main caveat is - most news outlets don't have an incentive to embed this widget unless many do and it becomes the norm (cause the credibility it gives them isn't worth the added effort). so you got a coordination problem.
but I'm optimistic. i know many news sources which i believe would like to become first adopters. and when you already have ~40 websites (plus all the fact checkers) it's easier to put pressure on larger outlets. until it's embedded at most places it should, and people become septic of those who don't embed it.
I'm not a developer but to me it doesn't seem very complicated to develop (correct me if I'm wrong). but i think it has great potential.
Please share your thoughts, and if you would be willing to help make this a reality in any way.