Instead we have a non profit set of standards which divide the internet into different layers. So you can have your ISPs, your web hosting providers, your websites etc. There is a healthy demarcation which prevents consolidating of power.
Maybe the way to breakup twitter/facebook etc is to create a set of protocols and divide them into layers.
For instance I should be able to register a username for tweeting like how you register a website name for DNS. Once registered you have a choice to store your tweets in any data hosting service.
Then a number of aggregate readers handle the front end user interface.
Each reader can have its own content filter and discovery algorithms. So even if your content is found offensive in one reader, you can just switch to another. If one is really addictive in a negative way, switch to a less intrusive useful version.