If cookies were little spies following your visitors around the internet, third-party cookies were the gossiping kind. Chrome is phasing them out. Safari and Firefox already did. So retargeting, behavioral audiences, and some of your favorite hacks are changing or disappearing.
Good news. You do not need spy cookies to do good marketing. You need consent, real relationships, and a clean data setup that does not freak out your legal teams. This guide shows exactly how to do that, all while giving examples you can walk into a meeting with tomorrow.
A cookie is basically a tiny piece of code your browser saves to remember stuff for later. First-party cookies are set by the sites you browse. They’re the reason your login stays put or your shopping cart doesn’t vanish mid-scroll. Third-party cookies come from outsiders piggybacking on that site, like ad networks following you across the internet. Cookies also vary by lifespan: session cookies disappear when you close the tab, while persistent ones hang around until they expire or you clear them.
understand: firstparty cookies are not the same thing as firstparty data. Cookies are a storage method. Firstparty data is any information you collect directly from your audience with consent.
Cross-site tracking is losing its edge, which means the infamous “shoe ad that follows you everywhere” is finally slowing down. Retargeting hasn’t disappeared yet, but it’s happening more inside walled gardens like Google, Meta, and LinkedIn, where your own first-party audiences matter most. Programmatic tools still exist, yet things like frequency capping and reach estimates are now less precise. Measurement has also shifted you get modeled conversions and controlled experiments instead of neat user paths. To fill the gap, Chrome is rolling out privacy-focused tools like Topics, Protected Audiences, and Attribution Reporting, which do help the situation a bit, but they don’t fully replace cookies.
A quick replacement cheat sheet
Zero-party vs first-party vs second-party vs third-party data (keep this straight)
Zero-party data:
Someone tells you on purpose. Preferences, quiz answers, “send me weekly, not daily.” This is the gold standard of data.
First-party data:
You observe on your properties with consent. Site events, purchases, support chats, email opens.
Second-party data:
Someone else’s first-party data that you use via a partnership.
Third-party data:
Mystery meat from aggregators you did not collect yourself. This is the one losing steam fast.
The golden rule: value for data
People share data when they get value. If you want emails, preferences, or quiz answers, offer something useful right away.
Examples of fair trades
- Newsletter with real insights, not sales spam.
- Quiz that gives a personalized plan or a score.
- Calculator: ROI, budget, timeline.
- Free template or checklist, no 20field form.
- Loyalty or referral perks.
- Preference center that lets users pick topics and frequency.
Consent done right
Getting consent right isn’t rocket science, but it’s where most brands still trip up. Start with banner copy that doesn’t sound like it was written by a lawyer. Try something like: “We use cookies to make the site work and to improve content. Choose your preferences. You can change them anytime.” Then accept people’s choices gracefully. Buttons should say exactly what they do: Accept all, Reject non-essential, or Manage preferences. Don’t lock down content unless the law in that region requires it. Respect the rules, but don’t overcomplicate things. And finally, make changing consent easy. A simple link in the footer is enough.
Your 6 part first-party data strategy
1) Get your foundation in order (consent and tagging)
– Add a consent management platform. Examples: OneTrust, Cookiebot, Sourcepoint. Pick one and connect it to your tag manager.
– Switch to serverside tagging if you can. Google Tag Manager Server, RudderStack, Segment. This reduces client bloat and protects data quality.
– Turn on Google Consent Mode v2 if you run Google tags in the EU or UK. This helps Google model conversions while respecting consent choices.
– Use GA4 or a privacyrespecting analytics tool. Track fewer, better events. Name them clearly.
– Configure Enhanced Conversions for Google Ads and CAPI for Meta so platforms can match conversions using hashed emails. Hashing is like scrambling the email into a safe ID.
2) Collect more zero-party data (ask nicely)
– Add a simple preference center linked from every email.
– Use progressive profiling. Ask for only one new thing each time: role now, budget later, timeline next month.
– Run a 2minute quiz that gives value. “Find your best plan” or “What is your AI maturity score.” Email the result.
– Create a couple of highvalue lead magnets. Blueprint, prompt pack, playbook. Keep forms short.
– Use SMS carefully. Ask for phone only when it is truly helpful. Promise low frequency and stick to it.
– Put “why we ask” under fields. It increases completion.
3) Identify visitors ethically
– Encourage lightweight login for key experiences. “Save progress” or “unlock your plan” works better than “create an account.”
– When you capture email, store a hashed version as your stable ID. Never send raw emails to ad platforms. Let the API hash it or hash before sending.
– Keep a firstparty cookie with your own anonymous ID to stitch sessions. Respect consent. If the user says no, do not set it.
– Do not fingerprint. If your team suggests it, walk away. It is a legal headache.
4) Enrich carefully
– Use enrichment to fill simple firmographic gaps for B2B: company size, industry. Use reputable vendors and only the fields you need.
– Explore clean rooms for partnerships: Google Ads Data Hub, Amazon Marketing Cloud, Snowflake Secure Data Sharing. Clean rooms let you match audiences in a privacysafe way without swapping raw data.
– Skip the creepy stuff. You do not need home addresses or sensitive categories.
5) Activate your first-party data
– Email and SMS: main characters now. Build journeys for onboarding, education, and reengagement. Segment by behavior and preferences.
– Website: use firstparty segments to swap headlines, proof bars, and CTAs. Example: if someone downloaded a pricing guide, show a scheduling CTA next.
– Paid media inside walled gardens:
– Google: send conversions with Enhanced Conversions, upload Customer Match lists, use valuebased bidding.
– Meta: set up CAPI and run Conversion Lift tests. Try Advantage+ for prospecting. Use your firstparty events to train it.
– LinkedIn: use Matched Audiences with company lists and contact lists, then layer skills or seniority. Great for B2B.
– Open web programmatic: lean on contextual and direct deals with publishers. Some will offer their own first-party segments. Test UID2 or RampID only if your legal team is comfortable.
6) Measure like an adult
– Modeled conversions: platforms will fill gaps using statistics. Accept it and validate with experiments.
– Incrementality tests: holdouts and geo splits tell you what is actually moving the needle. Simple and powerful.
– MMM (marketing mix modeling): even a lightweight model helps set budgets. Useful once you have 6 to 12 months of clean data.
– Cost per engaged account or cost per engaged user: good northstar for upper funnel work when userlevel tracking is limited.
Channel cheat sheet
Numbers that show progress
These numbers are a litmus test for your data setup. Remember, not hitting these numbers doesn’t mean your process isn’t working, it means you need some calibration.
-A healthy consent rate lives in the 65 to 85 percent zone but only if you speak plain and give people a reason to opt in.
-Hashed list match rates are doing fine If you’re in the 60 to 80 percent range on walled gardens.
-Flip on Enhanced Conversions or Conversations API and don’t be surprised when your attributed conversions jump 10 to 25 percent.
-For email, treat 25 percent opens and 3 to 5 percent clicks as a solid heartbeat as long as the list is kept alive and warm.
-And then there’s Customer Acquisition Cost (CAC) and Lifetime Value (LTV), the scoreboard that you need to worry about. Expect a little turbulence when you first switch, but by week six or eight, the numbers usually settle down.
Tiny toolkit (use what you already have where possible)
| Category | Tools |
|---|---|
| Consent | OneTrust, Cookiebot, Sourcepoint |
| Tagging & Data Pipes | Google Tag Manager (web + server), Segment, RudderStack |
| Analytics | GA4, Plausible, Matomo |
| CDP / Lightweight Hub | Segment, mParticle, Customer.io, Braze (for messaging) |
| Identity & Clean Rooms | Google Ads Data Hub, Amazon Marketing Cloud, LiveRamp, Snowflake clean room features |
| Measurement Helpers | Google Lift Studies, Meta Conversion Lift, Recast, Robyn |
Copies that might work for you. (feel free to steal)
Consent banner:
“We use cookies to run the site and make content better. Pick what you are comfortable with. You can change this anytime.”
From helper text:
“Why we ask: so we can send the right stuff.”
Preference center intro:
“No spam. You’re in control. Pick topics and how often.”
Common pitfalls you’d want to dodge
- Ask for too much too soon and people ghost you. Progressive profiling is your friend, collect details gradually instead of in one interrogation session.
- Treating every visit as a retargeting opportunity makes your brand look needy. Prove value on your site before you pop up elsewhere.
- Forgetting mobile is a rookie error. If the forms can’t be filled on a phone, people won’t bother.
- Skipping legal basics is reckless. Data retention, storage, and deletion rules are a modern standard and you must treat them like it.
- And fingerprinting? Not at all. It’s creepy. It’s unnecessary. And a solid first-party data setup makes it irrelevant.
Privacy Sandbox in one minute
The Topics API lets browsers share a few broad interest categories, like “sports” or “travel,” without the creepiness of tracking people across sites. Protected Audiences picks up the slack for remarketing in a cookieless world by running auctions directly in the browser, keeping user data in place. For measurement, the Attribution Reporting API provides ad performance insights without personal identifiers. Just expect modeled numbers instead of perfect precision. And while translation tools can help, they’re not magic, which is why building your first-party data muscle is still the most important move you can make.
Mini FAQ
- Are cookies dead?
Third-party cookies are on their way out in Chrome. First-party cookies stay. The web still works.
- Can we still retarget?
Yes, mostly through your own lists and inside major platforms. Open web retargeting is limited, not gone.
- What about B2B?
First-party shines. Use company lists, contact uploads, LinkedIn Matched Audiences, and content that earns emails from real buyers.
- Do we need a CDP?
Helpful once your volume grows. Not required on day one. Start with clean tagging and simple segments.
- Is modeled data reliable?
Good enough to run a business if you validate with experiments. Trust, but verify.
- Will privacy kill personalization?
No. It kills creepy. Honest personalization with consent performs better long term.
Wrap it up
Life after third-party cookies is not the end of good marketing. It is a return to basics with better tools. Ask for data the right way. Store it cleanly. Activate it where it counts. Measure with experiments instead of fairy dust. If you do those four things, you will be fine.
