In June 2022, it was made public that a chat bot named "GPT-4chan" (or "gpt-4chan") was trained by Yannic Kilcher, a machine learning expert, using 134.5 million /pol/ posts. He allowed ten such bots to post on /pol/ without restriction for two periods of 24 hours, mimicking human users. It made 15,000 posts during the first period: about ten percent of the total /pol/ posts during that time. Overall, GPT-4chan had posted 30,000 times in 7,000 threads. One iteration of GPT-4chan could be distinguished from most other /pol/ users by its Seychelles flag, displayed due to Kilcher's use of a proxy server. He used 4chan's paid "4chan Pass" service to bypass anti-spam restrictions (such as CAPTCHA). The influx of GPT-4chan posts gained attention from /pol/ users, with some suspecting a government agent or a dedicated team of posters. Some also suggested a bot could have been posting. The experiment had some lasting impact on /pol/, with accusations between posters of bot use continuing past the experiment's run-time. The bot frequently posted racial slurs and conspiracy theories. GPT-4chan gained significant attention among media and artificial intelligence (AI) researchers. Kilcher's GPT-4chan experiments, as well as his decision to release the underlying model for the bot online, were controversial. A letter entitled "Condemning the deployment of GPT-4chan" was signed by hundreds of AI researchers and developers. One AI ethicist with the Australian Institute for Machine Learning said that it violated "every principle of human research ethics". A DeepMind researcher said GPT-4chan "contributed to 4chan's echo chamber" and that it was "not impossible that gpt-4chan pushed somebody over the edge in their worldview". The Next Web commented that "[GPT-4chan] highlights AI's ability to automate harassment, disrupt online communities, and manipulate public opinion ... it also spread discriminatory language at scale." MIT Technology Review said, "Considering the material it was trained on, this outcome was depressingly inevitable." Hugging Face, the website where the bot's model was published, restricted access to it. The site's CEO stated: "[T]he experiment of having the model post messages on 4chan was [in my opinion] pretty bad and inappropriate [...]". However, he also said that it "brought interesting insights into the limitations of existing benchmarks by outperforming the TruthfulQA Benchmark compared to GPT-J and GPT-3". The Register added that, "GPT-4chan ... has some value for building potential automatic content moderation tools or probing existing benchmarks."