The first was Gemini Deep Research: https://blog.google/products/gemini/google-gemini-deep-resea... - December 11th 2024
Then ChatGPT Deep Research: https://openai.com/index/introducing-deep-research/ - February 2nd 2025
Now Perplexity Deep Research: https://www.perplexity.ai/hub/blog/introducing-perplexity-de... - February 14th 2025.