Starlink is literally an ISP, internet service provider. It will only create a "hookup" or an "on ramp" to the internet, just like any other internet service provider. Only difference is that Starlink is using new satellite technology to deliver Internet to anyone in range with a receiver. It's just like cable or fiber or DSL, where there's a way to deliver the information over an internet connection.

The type of infrastructure that runs Twitter would be more like server farms in various regions of the world all working together to always keep Twitter the website and all it's services accessible to anyone connected to the internet. There's all sorts of very technical stuff that goes on with these server farms to keep them all syncing, and running, balancing server loads and directing website or other traffic, etc. These server farms also have an ISP, which is separate, and then gets them connected to the broader internet where anyone can connect.

Starlink could never have the necessary bandwidth a server farm needs in order to transfer all the data needed for millions of active users at once. Starlink can work well for an individual house and the internet needs of a few people in one place, Especially compared to the current versions of satellite internet, but the lag and bandwidth limitations that come with connecting to a satellite would never work well for series server hosting. Starlink is essentially very good for getting high-speed internet to places where cable and fiber internet are not well suited, for people who until starlink wouldn't have proper highspeed internet In a remote location.