My question is – what trade secrets does Twitter even have that Meta didn't already have the existing infrastructure for, or competency to build themselves (probably better)?
None. There is no trade secret in building something like Twitter. Anyone on this site can probably make a clone of it.
The real secrets are the massive money needed to promote the network and to pay for the infrastructure, the massive social reach to attract top posters, the massive networking effect needed to make it a must-have app.
People on HN in particular tend to oversimplify large projects. Trying to build and maintain an app the size of Twitter would be hard. Trying to tie it into a functional advertising network would be harder. HN just tends to be brightly cynical about complexity in general; in reality there would be very significant challenges (as Musk is discovering now).
But do I buy that specifically Facebook could do it? Yeah, obviously they could. It's not at all surprising that Facebook could quickly launch a Twitter clone. This isn't like the "metaverse", Facebook already runs social networks that are larger and more complicated than Twitter is, and Threads looks to be highly tied into their existing infrastructure.
I could not build a Twitter clone in my free time, but I also don't currently run Instagram.
My guess would be stuff like upcoming products, business connections, contract details, way of doing business etc.
However I doubt that Musk has any grounds for claiming that "the most useless employees" who weren't even treated with dignity upon firing them would have transferred those to Meta illegally.
IMHO this is just Musk freaking out that the next time Twitter doesn't work as expected or asks for money, people would have real alternative to move on.
They definitely have existing products, knowledge and competency for building a twitter clone that could be adapted for this purpose (instagram/facebook posts & comment systems).
Knowledge is not automatically a trade secret. Skills from one job can be freely applied to another. The onus is on Twitter to prove that the employees took something specific (copyrighted code, a patented algorithm implementation, some other asset or IP) which is the property of Twitter and used it to build Threads. The last high profile lawsuit of this nature was Google vs Uber for stolen self driving tech, which had all of this and more.
Sorry if I was not clear, I'm saying that without hiring any Twitter folks, the Instagram folks could easily create a Twitter clone. Instagram posts & comments could be adapted pretty easily.
The question is whether the Twitter employees actually brought and used trade secrets for this effort.
The thing is these employees could have come in and directly used all the "knowledge and competency" they learned at Twitter to build Threads and it would still be 100% legal. There is a very high bar to proving whether any of it is actually a trade secret.
There's zero "trade secrets" (everyone knows how twitter works) and no technical secrets necessary. Threads is just instagram. It works and looks the same way. Instagram is photos with text, Threads is text with photos. The latter is not exactly rocket science to build when you already have built the former at scale and ran it successfully for years. And that's the genius of it!
The real secrets are the massive money needed to promote the network and to pay for the infrastructure, the massive social reach to attract top posters, the massive networking effect needed to make it a must-have app.
Meta already have all of those.