- The Measureverse
- Posts
- The Vegas rule is killing your data transparency
The Vegas rule is killing your data transparency
Jeff Sauer
October 02, 2025
In partnership with
One GA4 stream, ten vendor destinations
Your content security policy is probably unsafe.
And it's not your fault.
That's what Simo revealed in his latest MeasureSummit presentation on server-side tagging. Every marketing pixel you add forces you to punch holes in your security - adding "unsafe-inline" and "unsafe-eval" exceptions that make your CSP essentially worthless.
But there's a better way.
The Redundancy Problem
Open any marketing website and you'll see the same absurd pattern. Facebook pixel loads. Google Analytics loads. Google Ads loads. TikTok loads. Each one downloading JavaScript libraries, each one sending nearly identical data to different servers.
Same page view. Same conversion event. Same user information.
Sent separately to every vendor.
Simo calls this "an incredible waste of computation, battery life, and bandwidth." Your users pay for this redundancy with their data plans and device performance.
More importantly, every additional vendor domain increases security risk and requires CSP exceptions.
Data Stream Consolidation
The solution isn't revolutionary - it's logical.
Send one stream to your server container. Let the server decide what each vendor receives.
Simo demonstrated this with GA4 as the primary stream. One conversion event flows to the server, then fans out to Facebook, Google Ads, Pinterest, TikTok - whoever needs it. Same data, single transmission, complete control.
The benefits compound:
Fewer third-party requests
Cleaner content security policies
Better site performance
Retained data control
The Control Paradox
But here's where it gets interesting.
Server-side tagging promises control, but regulations, browser features, and business pressure all eat away at that control. You own the server container, but you're still constrained by the same laws and stakeholder demands.
Simo's advice? Don't use server-side tagging to collect more data. Use it to collect better data with more control.
"There's no virtue in getting a handful of more events. You use server-side tagging because you get to retain control and consolidate data streams."
The Transparency Problem
The biggest unsolved issue? Users can't see what happens in your server.
They see one GA4 request leave their browser. They have no idea it's being split and sent to ten different vendors server-side. Simo calls this "the Vegas rule" - what happens in the server stays in the server.
This opacity creates an ethical dilemma. You gain control as a data controller, but users lose visibility into where their data goes.
Practical Implementation
For those ready to experiment, Simo shared his approach:
Start with GA4 as your broad client-side stream. It already tracks everything you need and server-side GTM is built around GA4's event model.
Use parallel tracking - duplicate your existing GA4 tags and send copies to a test property and server container. Run both setups simultaneously until you're confident in the server-side data.
Add vendor-specific parameters (like Facebook event IDs) to GA4 events with prefixes, then strip them out server-side so they don't contaminate your analytics.
Stick to verified templates from vendors or trusted developers like Stape.
MeasureSummit 2025
Speaking of staying ahead of changes, MeasureSummit 2025 is next week - October 8, 9, 10.
Presentations like Simo's prove why this community matters. While others chase quick wins and data quantity, our speakers focus on sustainable, ethical approaches to measurement that actually solve problems.
Registration is still open for the free livestream. You'll get access to cutting-edge insights from practitioners who understand both the technical possibilities and ethical responsibilities of modern analytics.
The future of measurement isn't about collecting more data.
It's about collecting the right data with complete control and transparency.
Simo just showed us how.
To Your Measured Success!
--Jeff Sauer
Co-Founder of MeasureU
Find your next winning ad creative in seconds with AI
Most AI tools promise you thousands of ads at the click of a button. But do you really need more ads—or just better ones?
Kojo helps you cut through the noise. We analyze your paid social data to uncover the ideas with the highest chance of success. Then, our AI predicts which concepts will perform best, so you don’t waste budget testing what won’t work.
Instead of drowning in endless variations, Kojo sends your best idea straight to a real human creator who makes it engaging, authentic, and ready to win on social. The entire process takes less than 20 seconds, giving you certainty before you spend and better performance without the waste.
Why gamble on guesswork or settle for AI spam when you can launch ads proven to work, made by people, and backed by data?