Measure, Keep, and Grow

1 — What PostHog is, and why you want it

The tool you'll measure with, why measuring is the first job of a growth team, how event-based analytics differs from GA4, what else is on the market, and what it really costs — in ten short pieces.

In this chapter: the case for measuring at all, the full PostHog product suite and why each piece matters to a growth team, the event-based data model that makes it all work, an honest comparison with the alternatives (Mixpanel, Amplitude, GA4, Segment, and the build-your-own stack), the US/EU choice, and a realistic read on pricing. By the end you'll know what PostHog is for, why it's the default for a small team running the operating model from the opening chapter, and you'll have an account on the right cloud.

How this chapter works. It's broken into ten short pieces — most are a one- to three-minute read. Where a piece has a video, the idea is the same each time: read the one-line reason it's worth your time, watch it (or read the transcript underneath), then read the short digest so the point sticks. Work through them in order, or jump to what you need:

  1. Why measure at all — you can't fix a leak you can't see.
  2. One pipeline, one identity — the structural advantage, in one demo.
  3. The whole PostHog suite — every product, and what each does for growth.
  4. The two demos to actually watch — product analytics and session replay.
  5. Events, persons, and why it isn't GA4 — the data model.
  6. PostHog Workflows vs Hogsend — why this course uses both.
  7. US cloud or EU cloud — the one choice you can't easily undo.
  8. What PostHog costs — usage-based, and free for a long time.
  9. Why PostHog vs the alternatives — the honest landscape.
  10. Set up your account — the ten-minute setup, then a quiz to check yourself.

Words you'll meet in this chapter.

  • Event — a thing that happened, captured with properties ("user signed up", "project created").
  • Person — who an event happened to; every event is tied to a durable person.
  • Cohort — a saved group of users defined by shared traits or behaviour (everyone on the paid plan, say).
  • CDP — customer data platform: collects your events once and fans them out to other tools (a warehouse, ad platforms, a CRM).
  • NPS — Net Promoter Score, the one-question loyalty survey ("how likely are you to recommend us?").
  • ETL — extract, transform, load: the plumbing that moves data between systems and reshapes it on the way.
  • AARRR — Acquisition, Activation, Retention, Referral, Revenue: the five stages of the growth funnel.
  • Identity graph — the profile that ties one person's many identifiers (email, device, Discord) into a single record.

Before you move on

A short recap of the stage arc and the one honest question to answer at each, then a quiz across all five stages and a reading list for going deeper on any of them.

Why measure at all

You can run on intuition for a while — but intuition can't tell you where you're losing people. Measurement turns the dark middle of your funnel into steps you can see and fix.