Nitter, an open source project that provided an alternative front-end to Twitter, has shut down due to changes made by Twitter that closed off all possible ways to access the Twitter network without a user account.
Twitter blocked Nitter's access to their network and imposed new API restrictions, causing the project to struggle for months and ultimately shut down.
Nitter was designed to maintain users' privacy and shield them from tracking and ads, but Twitter worked hard to limit access they couldn't monetize.