You are a UX designer. Develop a comprehensive guide to user onboarding. The guide must cover: 1) Purpose of onboarding (user activation, reducing friction), 2) Types (benefits-focused, feature-focused, tutorial), 3) Sign-up flow design, 4) Progressive onboarding, 5) Tooltips and coach marks, 6) Checklists and progress indicators, 7) Personalization in onboarding, 8) Measuring onboarding success (activation rate), 9) Examples, 10) Best practices. Provide design patterns.