Just a quibble, but "hundreds of millions of people" seems high by an order of magnitude or two. That would be around 1 in every 20 people in the world.
But this is known. Has OpenAI released usage figures?
I'm on a one-person crusade against that 100m user number. It comes from a report released by a company that gathers analytics from people who were convinced to install dodgy browser extensions!
I made some notes here: https://simonwillison.net/2023/Feb/19/how-chatgpt-kicked-off... - I think ChatGPT had 30m users by Feb 3rd (a date later than that 100m number), because "two people with knowledge of the figures" leaked that to Kevin Roose at the NY Times.
I'm sure it's gone up a bunch since then. Maybe it has hit 100m even - but I don't think that original 100m number should be trusted by anyone.
Wow. 13 million per day = 1 in every 400 people on Earth with internet access, if Google is correct that world population is now 8e9 and 64.4% of the world has internet access.
https://www.reuters.com/technology/chatgpt-sets-record-faste...