Buying traffic · also called LAL, lookalike segment, similar audience
Lookalike audience
A lookalike audience is a targeting group an ad platform builds by finding people who resemble a seed list you supply, such as past converters.
You give the platform a "seed": a list of people who did something valuable. It studies what they have in common and finds others like them. On Meta the seed needs at least 100 people and the audience is sized as the closest 1% to 20% of a country. Google offers lookalike segments in Google Demand Gen, and has said that from 2026 they act as a signal for its AI and no longer as a strict boundary.
In search arbitrage the best seed is not "everyone who visited". It is the visitors who clicked a sponsored listing on the feed, ideally weighted by revenue. A lookalike built from them points the platform at people likely to search and click again.
Lookalikes matter less than they once did. Both big platforms now lean on broad targeting plus strong conversion signals, and treat audiences as suggestions. One ethical and practical caution: a seed built from accidental or incentivised clickers trains the platform to find more of the same, which the feed will eventually discount.
Think of it like this
It is asking a matchmaker: "Here are my ten best customers. Find me a thousand more who look like them."
Related terms
Broad targeting
Broad targeting means giving an ad platform few or no audience restrictions beyond country, age and language, and letting its algorithm decide who sees the ad.
Paid social
Paid social is advertising bought on social platforms such as Facebook, Instagram, TikTok, Snapchat and Pinterest, shown inside people's feeds and stories.
Google Demand Gen (Discovery)
Demand Gen is a Google Ads campaign type that shows image and video ads on YouTube, Discover, Gmail, Maps and the Google Display Network.
Meta Advantage+
Advantage+ is Meta's family of AI automation features that choose audience, placements, budget split and creative variations for Facebook and Instagram ads.
Conversions API (CAPI)
The Conversions API is Meta's server-to-server interface for sending conversion events and their values to Meta directly, without relying on the visitor's browser.
Sources: Meta for Developers: Lookalike audiences, Google Ads Help: Lookalike segments