Customer Match vs Similar Segments: What Replaced What
In short: Both were ways to put your first-party data to work in Google Ads, but only one of them still exists. Customer Match remains fully supported: you upload contact data and get a targetable, excludable audience. Similar segments - Google's lookalike product derived from seeds like Customer Match lists - was removed in 2023, with campaign-level automation absorbing the expansion job. If you are choosing today there is no choice: build Customer Match, and decide separately which automated feature gets to expand on it.
By the AdFlint research team · Fact-checked against current Google and Meta platform behavior · Last reviewed July 2026
Customer Match
Uploads hashed customer contact data to Google so you can target, exclude, or seed audiences from people you already have a relationship with.
You upload emails, phone numbers, or addresses; Google hashes and matches them against signed-in users, and the resulting list becomes targetable across Search, Shopping, YouTube, Display, and Demand Gen. Use it to suppress existing buyers, bid up loyal customers, or feed audience expansion. Match rates fall short of raw list size, and thin lists never reach the minimum required to serve at all.
Full definitionSimilar Segments
Google's retired audience expansion feature, which generated lookalike-style segments from a seed list before being removed in 2023 in favor of automated targeting.
Similar segments once derived a resembling audience automatically from a remarketing or Customer Match seed, and Google sunset them so campaign-level automation could do that expansion instead. Your seed lists remain valuable as signals feeding optimized targeting and Smart Bidding rather than as sources for a derived list. Advertisers still hunting for the setting almost always want optimized targeting or Customer Match.
Full definitionSide by side.
The differences that actually change what happens in your account.
| Customer Match | Similar Segments | |
|---|---|---|
| Status in mid-2026 | Fully supported and usable across Search, Shopping, YouTube, Display, and Demand Gen. | Removed in 2023 - the setting no longer exists to select and old segments stopped serving. |
| What you controlled | Exactly who is in the audience, because you supply every record. | Only the seed list; Google decided who resembled it and how far to stretch. |
| What does its job now | Nothing replaced it - it became the input other features consume. | Optimized targeting on Display and Video, and lookalike segments on Demand Gen. |
| Where your seed data goes | Directly targetable, or attached to ad groups as a signal for automation. | The same seeds now inform optimized targeting and Smart Bidding invisibly instead of producing a named list. |
| Reporting visibility | The list is a row you can segment, judge, and bid on. | Successor expansion folds into ad group totals - there is no lookalike row to inspect anymore. |
| What to do about it | Keep uploads fresh - seed quality is the lever you still control. | Enable optimized targeting or Demand Gen lookalikes and judge them on conversion outcomes, not audience names. |
What actually separates them.
Customer Match is still selectable in the interface, while similar segments cannot be chosen and stopped serving when Google removed them in 2023.
Similar segments produced a named, reportable audience, whereas the expansion that replaced them happens inside optimized targeting with no separate row to evaluate.
Customer Match quality is your responsibility through list hygiene, while lookalike quality was Google's model - and that model still runs, it just consumes your seeds silently now.
Demand Gen lookalike segments are the closest survivor of the two, but since early 2026 they default to guiding delivery as an AI-weighted signal rather than enforcing the reach tier as a strict resemblance boundary.
You used to cap expansion by simply not applying the similar segment; now you cap it by toggling optimized targeting off, which is a delivery setting rather than an audience choice.
Which one should you use?
Use Customer Match when
- You are building audiences today and need something you can actually select and apply.
- You want to suppress existing customers or bid up loyal ones, jobs a lookalike never did.
- You are seeding Demand Gen lookalike segments and want the cleanest possible buyer list as the source.
- You need the same audience definition working across Google, email, and other ad platforms.
Use Similar Segments when
- You are reading an older guide or audit that references similar audiences and need to translate it into current features.
- A legacy account still has ad group structures built around similar segments and you are deciding what inherits that budget.
- You want lookalike-style prospecting on Display or Video, which now means optimized targeting with your lists attached as signals.
- You want the closest thing left to a named lookalike audience, which today means Demand Gen lookalike segments, kept in mind that by default they now guide delivery rather than fence it.
Common questions.
Why can't I find Similar Audiences in Google Ads anymore?
Google removed similar audiences, also called similar segments, in 2023 and shifted the expansion job to automated features. Historical rows may still appear in old reports, but the segments no longer populate and cannot be added to targeting. Nothing is broken in your account - the product is gone.
What is the closest replacement for similar segments?
On Display and Video, optimized targeting with your remarketing and Customer Match lists attached as signals - it starts from your seeds and finds conversion-likely people beyond them. On Demand Gen, lookalike segments built from a seed list, though since early 2026 the reach tier you pick guides delivery as a default signal rather than acting as a hard resemblance boundary, with a legacy constrained mode available by opting out. On Search, Smart Bidding folds your lists in as signals automatically.
Do my old seed lists still do anything?
Yes, and arguably more than before. Attached to an ad group with optimized targeting enabled, they steer where the expansion starts, and Smart Bidding reads them when valuing auctions. A stale seed now quietly degrades several automated systems at once instead of just one lookalike, so upload hygiene matters more, not less.
Are Demand Gen lookalike segments the same thing as similar segments?
Same spirit, narrower scope, and less of a hard rule than it used to be. They exist only inside Demand Gen campaigns, you pick a reach setting that trades resemblance for scale, and the seed must be an audience list such as Customer Match - but by default Google now treats that reach setting as a signal it can expand beyond rather than a boundary it must respect, with a legacy constrained mode available by opting out. Similar segments were available much more broadly and enforced their boundary strictly, which is exactly why their removal pushed everything else toward optimized targeting.
Or stop choosing between them.
AdFlint picks the setting, writes the ads, and keeps optimizing inside the Google and Meta accounts you already own.
Related comparisons
- Affinity Audiences vs In-Market Audiences
- Custom Segments vs In-Market Audiences
- Customer Match vs In-Market Audiences
- In-Market Audiences vs Remarketing Lists
- In-Market Audiences vs Similar Segments
- Demographic Targeting vs In-Market Audiences
- In-Market Audiences vs Life Events Targeting
- In-Market Audiences vs Optimized Targeting