LLMs revisit Hacker News frontpages from 10 years ago (December 2015), with the benefit of hindsight. Each day's articles and comments are analyzed by ChatGPT 5.1 (with thinking + browser tool) to compare what was said to what actually happened and users are graded on how prescient they were in retrospect. 30 articles per front page and 31 of them => 930 GPT 5.1 Thinking calls led to total cost of ~$60.