Q1: How does GA4 identify traffic coming specifically from ChatGPT or the OpenAI app?

GA4 identifies this traffic through the `referrer` data passed by the browser or application. For web-based ChatGPT, the source often appears as `chatgpt.com`. For mobile app traffic, it may appear as `android-app://com.openai.chatgpt`. By utilizing GA4 Custom Channel Groupings and Regex, you can aggregate these various sources into a single "AI Traffic" metric for cleaner reporting.