Customer lists explained: privacy, hashing, consent and match rates

A customer list is a list of people you already know, such as customers, leads, trial users or event sign-ups. You upload it to PPCmate so you can show ads to them, or to people like them, on Google, Microsoft and Meta.

How the matching works

1. You give us e-mail addresses, either already hashed or as a file or CRM list that we hash for you.
2. Each address becomes a SHA-256 hash: a scrambled 64-character code that can't be turned back into the address.
3. We send the hashes to the networks you choose. Each network compares them with the hashes of its own users and tells us how many it matched.
4. Your ads can then reach the matched people.

What we store

• Only SHA-256 hashes of e-mail addresses (and mobile device IDs, if you upload those).
• When you upload a contact file or connect a CRM, each address is hashed the moment it arrives. The readable address is never stored, and no other columns or fields are kept.
• API keys and tokens are stored encrypted and never shown again.
• Your lists are yours. They're never shared with or used for any other advertiser.

Your permission

Every list needs your confirmation that these are your own customers or contacts and that you may use them for advertising. Only upload people who gave you their details directly and agreed to hear from you. Bought or scraped lists break Google, Microsoft and Meta rules, and can get the list refused. How we share lists with the networks is described in section 14 of the PPCmate privacy policy.

How big a list needs to be

• Plan for at least 300 people. Below that, no network will use the list.
• Microsoft: about 300 matched people.
• Google: about 1,000 matched people for Search, about 100 for Display.
• Meta: shows only a size range and hides very small lists.

Match rates and "low reach"

Networks can only match people who use the same e-mail address with them. A personal Gmail address matches often. A work address like anna@company.com matches far less often, because people rarely sign in to Facebook or Google with it. That's why connectors say Expected reach: low for B2B lists. It's normal, not an error.

To get more matches: include personal e-mails if your CRM has them, upload bigger lists, and combine lists with company or job targeting (Microsoft Audience campaigns: B2B targeting by company, industry and job function).

Next: Customer lists: upload a list and use it on Google, Microsoft and Meta.