I wonder if this means "double jepoardy" is in play: once youtube gets this easily-dismissed lawsuit cleared away, no one can sue youtube again about state of DMCA takedowns on the site.
No, because:
(1) “Double jeopardy” applies to criminal charges only.
(2) “Double jeopardy” applies to charges for conduct that is part of the same transaction, not a similar pattern of conduct carried out at different times against different people, much less suits whose similarity is that they are merely in the same broad category (“has something to do with how DMCA takedown notices are handled”.)
As a general rule, you can’t lose the right to file a civil suit because of a lawsuit you didn’t participate in. (Class action might seem to be an exception, but class members are viewed as participants unless they opt out, so its technically not.)
The same evidence used against you in your second trial might be useful in getting any lasting legal consequences of your first convinction expunged and negated as a wrongful conviction, but that’s likely to be of limited value if you are convicted of the second crime (though it might be useful to negate three-strikes or other repeat-offense enhancements.)
His wife is subsequently tried for the murder that she did not commit, and found guilty. She then goes to prison and serves out the sentence for this murder. While in prison she learns that her husband is not actually dead and instead had framed her in order to start a new life. So after she is released from prison, having completed the sentence for her crime, she then proceeds to track down and publicly murder her husband.
Because of Double Jeopardy, she can not be tried again for the same crime of murdering her husband. She had already been found guilty of it and had already served the sentence for the crime. She argues that it is not possible to murder the same person twice. So she is simply acting on the crime that she had already been convicted and punished for.
If she were to go murder her friend or colleague after getting out of prison that would be a different murder and Double Jeopardy wouldn't apply. But murdering the husband that she has already served the sentence for is the same crime she already was found guilty of and can not be convicted of again.
A Famous REAL LIFE example of this would be OJ Simpson. He was found NOT GUILTY in the 1994 murders of his ex-wife and friend. Since then he has basically publicly confessed to having murdered them (via an interview with FOX). He has also written a book where he writes in detail how he "would have" murdered them. His book publisher has also come out and claimed that he admitted to the murder to his publisher. The reason he can be so careless about these confessions is because he can not be tried for this crime again. He was already tried for it and found "not guilty" so even if new evidence (or a full-blown confession) comes to light, he can not be tried for it again under the protection of Double Jeopardy.
Historically it was possible in England and Wales to re-try people in some particular extreme cases. For example if prosecutors could show tampering with the jury allowed you to get off, they can get the High Court to run a new trial, having presumably successfully convicted people (maybe including you) for the jury tampering meanwhile. Or if the original trial judge made a decision that is manifestly wrong e.g. you're on trial for murder, the judge says you seem like a nice man, acquits you on the spot, that can be appealed because a jury was never asked about it.
But in 2003 as a result of the fall out from the murder of Stephen Lawrence (basically a bunch of white guys murdered a teenager apparently for being black but they weren't found guilty of murder) the law was changed. Now it's possible for prosecutors to go to court to get the court to decide that your original acquital was unsafe (the same way they'd decide if e.g. new CCTV evidence showed you were actually half way across the country at the time of a crime your conviction for that crime is unsafe and should be undone) and order a new trial. This option is only open for a handful of offences like murder or kidnapping.
Historically it was possible in England and Wales to re-try people in some particular extreme cases
I assume in real life she could be found guilty of killing the husband in modern day, a separate crime from killing the husband in the past.
OJ is a good example, but different than in the movie since there's only one murder back in 94, not two supposed murders on two separate events.
If I am accused of killing a man, and I am proven innocent, I cannot be accused of killing THAT SPECIFIC MAN again. If I was to go and kill a man, I cannot claim "but I was already exonarated for killing a man". Because it is not the same crime. DJ is all about being prosecuted for _the same instance of a crime_ more than once. Not that once I broke a law, I cannot break it again in the future.
This can apply to civil cases if a judge dismisses the case with prejudice, which means that this specific case cannot be put to trial again. Sometimes a judge dismisses the case without prejudice which indicates that the judge felt there was a case, but not enough supporting evidence yet. If a case is not resolved, it goes up the chain of courts, eventually a court may reject the case, in which case a lower court's ruling takes hold. If a case is resolved I cannot go to trial for that same case again. Nor can I use the exact same evidence for a new case. Or rather... I can but it will get dismissed with prejudice.
There is technically nothing stopping me from filing cases against you which were already resolved to harass you. But after like 2 times my lawyer's license will be revoked and possibly I will have a case against me for obvious harassment forcing me to cover any legal expenses. Overall courts really really don't like it when you act in bad faith, even if not criminally.
Nitpick: It's actually that you can't be accused of the SPECIFIC INSTANCE of killing that man.
I only say this because there was a movie with a plot of a husband faking his death and the wife being convicted for it. The movie implies that the wife could find and kill the guy and not be tried because she'd already been convicted of killing him. While only one person was murdered, it was the two separate acts of killing the person that are the offenses, so double jeopardy would not apply.
In the situation of the movie though... it would get really complicated real fast.
But yes, specific instances. Though its not like the cops can say 11:59am. Nope next case is for 12:00pm. And now another case for 12:01pm. This is where the judge's judgement will be used.
I'm sure in the exact scenario of the movie this will end up in the supreme court.