Claude is the assistant made by Anthropic, and the main alternative to ChatGPT. It comes as a chat app, but also as a family of models in different sizes (historically named Haiku, Sonnet and Opus, from fastest to most capable) that businesses build on through the API.
Claude has a particular following among people who work with words and code. Writers tend to praise its prose and its ability to hold a voice. Developers made Claude Code, its terminal-based coding agent, one of the defining tools of the AI building boom.
Why you keep hearing it
Because it is one of the "big three" assistants alongside ChatGPT and Gemini, and because a noticeable share of AI practitioners name it as their daily workhorse. When AI-savvy people compare notes on which assistant wrote something well, Claude usually enters the conversation.
What it means for you
If your work is writing-heavy (and marketing is), Claude belongs in your comparison set. The practical move is to run the same real task through Claude and ChatGPT for a week each and judge by your own output, not by anyone's benchmark charts.