OpenAI ChatGPT (GPT-3.5)
OpenAI introduced ChatGPT modestly, as a "research preview" of a model fine-tuned from the GPT-3.5 series and trained with reinforcement learning from human feedback (RLHF) to follow instructions and hold a conversation. The pitch centered on dialogue: the model could answer follow-up questions, admit mistakes, challenge incorrect premises, and decline inappropriate requests. OpenAI explicitly flagged limitations up front, noting it could write plausible-sounding but incorrect answers and was sensitive to phrasing, framing the release as an iterative deployment to gather feedback rather than a finished product.
ChatGPT shipped on November 30, 2022 as a free, public, browser-based chat interface, no waitlist, no payment, open to anyone who signed up. There was no API and no paid tier at launch; both came later (ChatGPT Plus in February 2023, the API in March 2023). It ran on a GPT-3.5-series model that had finished training in early 2022.
This was the launch that mattered, and its impact came almost entirely from packaging rather than from a new frontier model. The underlying capability had largely existed in GPT-3.5 for months; wrapping it in a free, zero-friction chat interface turned an obscure developer tool into the fastest-adopted consumer software in history, roughly one million users in five days and an estimated 100 million within two months. It created the generative-AI category in the public and boardroom imagination, triggered a competitive scramble (Google's "code red," the Microsoft partnership escalation, a wave of enterprise pilots), and reset expectations for what software could do. The hindsight caveats are real: the launch model hallucinated freely, had no live web access, a knowledge cutoff, and no reliability guarantees, and "research preview" framing understated how quickly people would treat its output as authoritative. The durable lesson is that distribution and interface, not raw model scores, drove the inflection point.
ChatGPT is the event that put AI on every executive's agenda and proved that user experience, not benchmark supremacy, decides adoption. It marks the start of the period your competitors, customers, and employees began using AI directly, whether or not your organization had a plan.