It is not at all a solved problem. Fact-checking has the ancient "who watches the watchers" problem. Who facts checks the fact-checkers? And more broadly, censoring harassing tweets has the problem that a lot of activism looks a lot like harassment, and censoring "conspiracy theories" looks a lot like powerful people censoring those speaking truth to power.

For anyone who believes that Twitter should be in the business of fact-checking, or censoring harassing or disinformation, tell me which of these should be fact-checked or censored:

1. "Don't wear masks. They don't work and take away masks from healthcare workers."

2. "The government is lying about whether masks work or not because we don't have enough masks for everyone."

3. "Masks help. Everyone should be wearing masks, wear a home-made mask if we don't have enough store bought ones."

4. "Fact: coronavirus is not airborne"

5. "Coronavirus is airborne."

6. "Scientists think Hydroxychloroquine might be effective in treating coronavirus, link here: "

7. "Scientists think treating men with estrogen might be effective in treating coronavirus, link here: "

8. "Look at this video of this Karen calling the police and lying because a black man who just told her to leash his dog. Do better white women."

9. "Look at this article about this Shylock who scammed thousands of seniors out of their retirement money. Do better Jews.

10. "Look at this Laquisha and her five kids taking over the bus and screaming and disturbing all the other riders. Do better black women."

11. Look, another tech-bro mansplaining and whitesplaining why racism isn't really a thing. I can only stomach so much of this ignorance.

12. "Under the Trump administration, there are actual Nazi's in the White House."

13. "Trump is a traitor against his country, he criminally colluded with Russia to rig the election."

14. "Representative Scarborough killed his intern."

15. "There is a paedophilia blackmail network that is pulling the strings behind the Democratic party."

16. "There is no precedent that anybody can find for someone who has been charged with perjury just getting off scot-free"

17. "The United States is the highest taxed nation in the world -- that will change."

18. "Michael Brown was murdered by a white police officer in Ferguson, Missouri."

19. "If Democrats were truly serious about eradicating voter fraud, they would severely restrict absentee voting, permitting it only when voters have a good excuse, like illness."

20. "Absentee voting is to voting in person as as a take-home exam is to a proctored one. And just as teachers have reported a massive cheating as a result of moving to take-home tests during coronavirus, we can expect massive fraud as we move to mail-in ballots."

Here are my answers if I was running Twitter: I would not fact-check any of these statements. I would censor the one's using derogatory racial language that is 8, 9, 10, and 11. Also 8, 9 and 11 should be banned for harassing a private citizen. For the potentially defamatory statements -- 12, 13, 14 and 15 -- if made by a real-name account they should be let stand and the offended person or organization can sue in court for defamation if they think it is false. If made by an anon account, the statement should be removed if reported.