The EU is barrelling head first towards being a tech backwater. Unlike China it probably isn't going to implement internet censorship muscular enough to stimulate a set of competent home grown competitors; the Commission always likes to make other people do its dirty work so they'll expect the products themselves to do blocks but the incentives to make those blocks stick aren't really there beyond tickbox compliance. People stuck in member states will just use VPNs or other workarounds, and nobody will pony up the sums needed to build genuine competitors. In turn this means that the EU won't develop home grown replacements to unavailable services or any of the other products people already use, because it's just far too risky to invest the huge sums required when at any moment the Commission might arbitrarily change its mind (something it does regularly) or your target market just gets used to convoluted workarounds.
IMPORTANT: To all US tech firm employees reading this. Please remember that not everywhere in Europe is in the EU. The UK, Switzerland, Norway, Ukraine, Serbia, Iceland, Lichtenstein and a whole host of smaller countries are not. Over-blocking is already a big problem for people living in these countries due to things like the GDPR.
I am sorry but what makes you believe that the EU citizen and bureaucrats really want twitter that much? It's not power, water, or food production? It's just a website... If twitter disappeared, the next day something would take its place in the EU.
If a foreign company don't want to accept the laws of a country, they can leave, that's fine. I mean, I am sure that the bureaucrats would like nothing more than having a EU company taking over.
I like the fracturing, reduces the global hegemony of a single corporate entity controlling global communication.
I'm also in that camp....no more twitter, EU competitors would flourish.