The 'desired action' varies by context: completing a checkout (ecommerce), submitting a form (lead generation), starting a free trial (SaaS), or clicking a CTA (content marketing). The same site has different conversion rates for different actions.
Industry benchmarks: ecommerce sites average 1–3% checkout conversion; SaaS landing pages 2–5% for trial sign-up; B2B lead forms 5–15% depending on offer quality. A site significantly below benchmark usually has friction (slow load, broken checkout, confusing form) rather than a copy problem.
Conversion rate alone is not the goal — conversion rate × traffic × average order value × repeat rate is. A site can lift conversion rate by aggressively discounting and end up with a worse business. Always look at conversion rate alongside the rest of the unit economics.