ChatGPT is joining the likes of Gemini and Perplexity to launch its own free Deep Research tool. You can now use ChatGPT to generate in-depth reports on any topic you like. However, there are usage limits and feature limitations to be careful about,

The lightweight version of Deep Research will be as in-depth as the standard version, but produce shorter answers.

Creating a new kind of deep research tool is an attempt from OpenAI to reduce the heavy usage of existing deep research modes it's seeing from users. These kinds of queries can be more expensive for AI providers to execute, due to their process of running more complicated commands and returning more information.