Twitter, known as X since 2023, is a news and microblogging service provided by the San Francisco-based X Corp. with branches in San Antonio and Boston. The network allows you to post short text messages of up to 280 characters called tweets, which appear on the user's home page. Users can follow other users in order to view their tweets on the site's home page, which is a bulletin board where the tweets selected for the user are listed.

By default, tweets are public and can be broadcast privately, showing only to certain followers. Users can tweet from the service's website with official external applications or via the SMS service available in some countries. Although the service is free, accessing it via SMS incurs support fees set by your mobile carrier.

On October 27, 2022, Twitter was purchased by Elon Musk, CEO of SpaceX and Tesla.

The set of posts published on Twitter by users constitutes an enormous quantity of material, which can also be used by companies: for example, Dell has opened a communication channel with its customers on Twitter and many services offer monitoring of the reputation of brands on Twitter. Even in Italy some companies, universities, schools and public administrations use Twitter for educational purposes.