What is the marketing funnel, and what metrics matter at each stage?

The funnel maps the journey from unaware to customer, and each stage needs different tactics and different measures.

• Awareness (top) — the prospect learns you exist. Tactics: content, SEO, social, PR, display, video. Metrics: reach, impressions, traffic, brand search volume, share of voice.
• Consideration (middle) — they are evaluating options. Tactics: comparison content, case studies, webinars, email nurture, retargeting. Metrics: engagement rate, time on site, return visits, email open and click rates, lead volume.
• Conversion (bottom) — they act. Tactics: product pages, demos, trials, offers, sales enablement. Metrics: conversion rate, cost per acquisition, lead-to-customer rate, revenue.
• Retention and advocacy — after purchase, and where most of the profit actually is. Metrics: repeat purchase rate, churn, customer lifetime value, net promoter score, referrals.

Note: Two points worth making. First, the funnel is a model, not a description — real journeys loop, skip stages, and involve multiple people, which is why last-click attribution systematically undervalues the top. Second, the interesting analysis is finding where the biggest drop-off is: a 1% improvement at the widest leaking stage is worth more than a large improvement somewhere narrow. Marketers who only optimise the bottom of the funnel eventually run out of people to convert.