Following Twitter gave a small reality check to one of President Trump's tweets, the President threatened to 'shut down' social media companies, attack a Twitter employee directly and signed an executive order concerning the Internet as a whole.
This is the most recent defense in a long-winding rivalry between the president and his favorite. Though he has been on Twitter since 2009 and has more than 80 million followers, Trump has long been moaning about what he thinks of the anti-conservative bias on the site (but without any evidence). Even if their terms of service have not been broken so far, Twitter has agreed not to delete or change Trump's messages.
In contrast, Facebook refused to delete posts similar to the tweets of the President.
There are legal challenges to the Executive Order.