Technology

Before DeepSeek Blew Up, Chatbot Arena Announced Its Arrival

A crowdsourced rating system for chatbots has become the way AI insiders learn which models work best.

Illustration: Patrik Mollwing for Bloomberg Businessweek

For most of the world, DeepSeek seemed to explode out of nowhere in January with open-source artificial intelligence software that rivaled models from OpenAI and Google—and was built, purportedly, at a fraction of the cost of competitors’ models.

For fans of a website called Chatbot Arena, however, it was a bit of an eye-roll moment: They’d been watching—and rating—the progression of models from the Chinese company behind DeepSeek for months.