Scroll depth tracking is implemented

Scroll depth tells you whether visitors actually read the page or bounced after the hero. Without it, a visitor who scrolls past every pricing tier, reads every testimonial, and leaves looks identical to one who bounced after two seconds. You cannot distinguish content that holds attention from content that fails, cannot identify the fold where engagement drops, and cannot quantify the impact of page length experiments. Long-form marketing pages become uninstrumented.

If you use GA4, enable Enhanced Measurement in Admin > Data Streams > your stream > Enhanced Measurement > Scroll. For PostHog, Mixpanel, Plausible, or custom setups, add explicit tracking in lib/scroll-tracking.ts:

const milestones = [25, 50, 75, 90]
const fired = new Set<number>()
window.addEventListener('scroll', () => {
  const pct = (window.scrollY / (document.body.scrollHeight - window.innerHeight)) * 100
  milestones.forEach(m => { if (pct >= m && !fired.has(m)) { fired.add(m); analytics.track('scroll_depth', { percent: m }) } })
}, { passive: true })