The closing point about measuring signups per AI referral is the part I'd start with. A practical way to set it up: add chatgpt.com, perplexity.ai, claude.ai and gemini.google.com as a custom channel group in GA4, then compare signup rate against organic for the same 30 days. Next, test your buying-intent pages directly. Ask ChatGPT or Perplexity: "I'm a [role] at a [size] company, comparing [category] tools for [use case]. Shortlist three with reasons and objections." Note whether you're named and which pages get cited. Finally, fix the gap pages first, usually pricing, comparison and implementation, with a plain one-paragraph answer at the top. Re-run the same prompts monthly so you have a trend, not a snapshot.