James Hawkins stared at the data pouring into PostHog every day. Session replays. User clicks. Error logs. The kind of granular product insight that most companies would kill for. Yet turning that firehose into proactive intelligence demanded something more than off-the-shelf models. So PostHog decided to train its own. The announcement landed on May 27. Customers on the US cloud would opt in by default. EU users stay out unless they choose otherwise. Data gets anonymized. Training starts June 29. No selling to third parties. The goal? Smarter session replay analysis at scale. Synthetic user testing before code ships. Predictions that nudge conversion rates higher without burning extra tokens. “I really think we’re on the verge of some of our best work through the next six months,” Hawkins wrote in the PostHog blog post . Simple on paper. Brutal in practice. Frontier AI training costs have climbed 3.5 times per year since 2020. They double every seven months. Power demands double annually too.…