---
title: "Audience syncing: closed-won lookalikes and exclusion lists | Cometly Academy"
description: "Lookalike audiences are only as good as the seed list. Most teams seed Meta and LinkedIn lookalikes from a CRM export that’s 3–6 months old, full of churned customers, and missing offline-only deals. Cometly keeps a live audience of paying customers, MQLs, and high-intent visitors synced to your ad platforms in real time."
source: "https://www.cometly.com/academy/audience-syncing-lookalikes-and-exclusions"
---

# Audience syncing: closed-won lookalikes and exclusion lists

Send the platforms more buyers and fewer freeloaders.

- Module 04: Ad Platform Optimization
- Lesson: 4.4
- Track: Both
- Format: Strategy
- Read time: 6 min

Lookalike audiences are only as good as the seed list. Most teams seed Meta and LinkedIn lookalikes from a CRM export that’s 3–6 months old, full of churned customers, and missing offline-only deals. Cometly keeps a live audience of paying customers, MQLs, and high-intent visitors synced to your ad platforms in real time.

## Key takeaways

- Sync 'paying customers' as a high-intent lookalike seed (refresh weekly)
- Sync 'churned customers' and 'free-only users' as exclusion audiences
- Sync 'engaged accounts' for ABM retargeting — including non-form-fill engagers
- Use 1% lookalikes for tight match, 5–10% for prospecting
- Refresh seeds at least monthly so the audience reflects your current ICP, not last quarter’s

Lookalikes are the highest-leverage audience asset on Meta, Google, and LinkedIn — but their quality is bottlenecked entirely by the seed list. A clean, current, high-fit seed produces lookalikes that significantly outperform broad targeting. A stale, unfiltered seed produces lookalikes that perform like broad.

## Why it matters

Most teams seed lookalikes once and forget about them. The seed list ages, includes churned customers, and gradually drifts away from your current ICP. Cometly keeps the seeds live by pushing your customer list (with appropriate filters) to each platform on a weekly cadence.

## Which seeds to sync

Sync at least three audiences: paying customers (the inclusion seed), churned and free-only users (the exclusion seed), and engaged accounts that haven’t yet converted (the retargeting seed for ABM).

For SLG: also sync 'closed-won pipeline by deal value' as a value-based custom audience — which lets the platforms run value-weighted bidding on lookalikes.

For PLG: sync 'paying customers by plan' so you can build separate lookalikes for high-LTV plans (Pro Annual, Enterprise) versus low-LTV plans.

- Paying customers (inclusion seed) — refreshed weekly
- Churned/free users (exclusion seed) — refreshed weekly
- Engaged accounts (retargeting seed for ABM) — refreshed daily
- By-plan or by-deal-value seeds for value-based bidding

## Lookalike sizing

1% lookalikes are tight matches, best for high-intent retargeting and remarketing. 5–10% lookalikes are looser, best for prospecting at scale. Run both concurrently as separate ad sets and compare performance — most teams find the right mix is somewhere in the middle.

Refresh seeds at least monthly. A six-month-old seed reflects last quarter’s ICP, not this quarter’s, and lookalikes built from it will trend toward your old customer base.

## Common pitfalls

### Seeding lookalikes from the wrong list

All-customer lookalikes include churned and low-LTV users. Filter to active high-LTV plans or active pipeline.

### Forgetting exclusion audiences

Without exclusions, you’ll keep paying for impressions to existing customers and free-tier users. Sync exclusions as aggressively as inclusions.

### Letting seeds go stale

Six-month-old seeds drift. Refresh weekly for paying customers, daily for engaged-account audiences.