X revamps terms and sues to defend the ‘Twitter’ trademark after startup challenge

X, the social media platform formerly known as Twitter, has revised its Terms of Service and launched a legal countersuit as part of an effort to solidify its claim to the iconic 'Twitter' trademark after a new challenge threatened that intellectual property.

Under the updated Terms of Service — set to take effect on January 15, 2026 — X now explicitly states that users may not use the Twitter name, trademarks, logos, domain names or other brand features without the company’s written consent. The revision marks the first time the service’s terms have named 'Twitter' alongside 'X' in this context. Previously, only the current brand was referenced. The change also makes minor updates relating to EU law and age-assurance technology.

The move coincides with a trademark dispute with a Virginia-based startup, Operation Bluebird, which this month petitioned the U.S. Patent and Trademark Office (USPTO) to cancel X’s rights to the Twitter and Tweet marks on the claim they were abandoned after the rebranding to X. Operation Bluebird has also filed its own application to register the 'Twitter' trademark for use with a proposed platform called Twitter.new.

X’s countersuit, filed in response, is part of a broader legal strategy to assert that the Twitter brand remains active and associated with the company despite the rebrand. The dispute has also played out in parallel litigation: X Corp recently filed a federal lawsuit against Operation Bluebird in Delaware, alleging trademark infringement and consumer confusion over use of the Twitter name.

Experts note that under US trademark law, rights can be lost if a mark is not actively used — the basis of the startup’s petition — but companies often defend famous marks by demonstrating continued use or public association. X maintains that users continue to access the platform via the legacy twitter.com URL and that the brand still holds enduring recognition.

The legal contention highlights how intellectual property continues to matter in the digital age, particularly for legacy brands that have undergone major rebrands. As the case unfolds, it could influence how technology companies approach trademark rights following structural identity changes.