How Reddit lookalikes work

Seed quality decides#

Model buyers, not browsers: purchaser and high-value-event seeds outperform all-visitor seeds by distance. Small or stale seeds produce confident nonsense, so build seed volume before expecting lookalike magic. When seeds fall short, engagement audiences and interest expansion bridge the gap honestly. Seed rules: Reddit custom audiences help.

The thresholds#

Ten thousand site users or one thousand matched list users minimum. Below that the audience will not build; near that it builds slowly and learns slowly. Budget lookalike tests to clear learning like any prospecting group, and judge on CPA against community baselines rather than volume alone.

Test against rooms#

Lookalikes compete with community clusters, not with nothing. Run the same creative into lookalike and community groups simultaneously and fund the winner. Modelled reach often wins on volume and loses on efficiency; knowing which matters decides the budget. Testing order: creative-first testing.

Refresh the seed#

Seeds decay as behaviour shifts and seasons turn. Rebuild lookalikes from fresh converter windows regularly, retire audiences whose CPA drifted, and version them by seed date so staleness is visible. A lookalike is a photograph of buyers, not a portrait; retake it often. Signal upkeep: Pixel setup.

When to skip#

New accounts without seed volume, niche offers where 10,000 converters is fantasy, and privacy-constrained verticals should skip lookalikes without shame. Community targeting plus keyword expansion covers the same ground with better intent. Fit check: Reddit custom targeting.

Putting lookalikes into practice#

Build purchaser-seed lookalikes the moment seeds qualify, test against community controls with matched creative and budgets, judge on CPA over a full window. Winners join the expansion rotation; losers get archived with the seed notes that explain them.

Rebuild quarterly from fresh converter windows and version by seed date. Stale seeds model yesterday buyers for tomorrow budgets. Rotation: scaling winners and custom audiences.

Frequently asked questions#