The catch would be if they used proprietary knowledge or trade secrets from their old jobs in their new jobs, which actually could be an issue and alluded in the threat letter. Just hiring them is not necessarily an issue and near impossible to enforce in most places anyway
Now, how much they can prove and how much actually happened is a different kettle of fish, altogether. The claim that any Twitter employees hired didn’t work on Threads is very plausible. It’s been stated repeatedly in this thread - the challenge for Twitter isn’t a technological one. The underlying technology itself for basic tweeting is not that complex.
Seems pretty likely this was just Musk telling his lawyers what to do. Can’t be much bite behind the barking. And Threads or whatever, along with several other similar apps, was likely in some stage of development well before Musk went on his firing spree.
Now hold on here. Musk isn’t Twit CEO. He’s just an innocent board member. He and the others get together a few times a year for refreshments and friendship.
If Zuck pays a couple of billion in legal costs to kill Twitter and grab a significant percentage of their user base, it will be money well (and cheaply) spent.
They’re all Star Trek characters. First guy is Zephraim Cochrane, a genius scenitist who invented the warp drive. In Star Trek: First Contact, the crew travel back in time and meet him, and are disappointed that he invented the warp drive primarily to get rich. Once he gets in space, though, he has a “road to Damascus” moment and becomes less concerned with wealth, and more with human advancement and discovery.
The second is a Ferengi, aliens whose culture is based on extreme capitalism. They’re an advanced space-faring civilization, but only care about profit, to a literally religious degree.
The third is a Pakled. Their demeanor is comically stupid, and they get all their tech by stealing it from other civilizations who underestimate them because they seem so dumb.
I’m more than happy for Musk to lose that lawsuit and get stuck for exorbitant fees. But objectively, it was definitely a case of the law firm raiding the coffers while they could. It’s tough to justify it if it wasn’t specifically spelled out in the contract.