Hi. I'm Julien Le Nestour, Head of Consumer Science and Analytics at Havas Australia.

I deliver growth by connecting disciplines most marketers keep siloed—behavioral science, data architecture, tracking, privacy, media performance, CRO, SEO, and CRM.

Opinions here are my own and not those of my employers.

I'm hands-on across all of these. Throughout my career, I've coped with ADHD by learning new disciplines successively and being technically hands-on with each, not just as a strategist or manager. This gives me actual knowledge of the work my teams and clients do. It's also proving very useful for building agentic workflows.

I'm also brutally honest. If I don't know something, I'll say it. If you're making a mistake, I'll say it. If I can't deliver value, I'll also say it. This doesn't make me a good salesperson, but it does make me a trusted advisor—as my client relationships spanning many years demonstrate.

Over the years, I've accumulated expertise and opinions on many topics but haven't taken the time to share them. My ambition in 2026 is to finally do it. AI is the catalyst.

First, as an enabler: this site is built with AI. I dictate, brainstorm, and edit with Claude 4.5 and GPT 5.2. (Gemini 3 is the sometimes useful idiot for me, though it may not be for you.)

Second, as the driver of urgency: the pace of change is nuts if you're hands-on at the frontier. I see many blind spots and opportunities that need to be seized now.

What I Write About

Behavioral Science & User Behavior

Understanding how humans actually behave prevents mistakes. Most optimization work fails because it assumes rational behavior. My starting point for any recommendation: "What will the user actually do?"

Data & Measurement Systems

You can't improve what you can't measure accurately. I write about building measurement systems that actually inform decisions—not dashboards that look good in meetings but mislead teams about what's working.

Tracking Architecture & Privacy

Getting performance and staying compliant requires deliberate architecture. I cover OAIC compliance (which isn't GDPR), data minimization, consent strategies, and building tracking systems that are both defensible and performant.

Signal Quality & Media Performance

Weak or inconsistent conversion signals starve algorithms. I focus on signal quality, value-based bidding, and the data foundations that make automated bidding actually work—particularly when privacy constraints limit addressability.

LLM Optimization & the Shift from Search

Keyword-based search is becoming AI-mediated discovery. I write about structured data, entity authority, content that models can understand, and preparing for a world where ChatGPT recommends products instead of Google showing ten blue links.

Customer Experience as a System

Touchpoint optimization without understanding the whole lifecycle is guesswork. I approach CX systematically—connecting behavioral science, journey data, and lifecycle strategy to drive retention and reduce friction.

Ad Operations & Cross-Platform Measurement

I write about the operational reality of deploying campaigns at scale: reconciling contradictory data sources, managing multi-vendor ecosystems, and building processes that survive platform changes and team turnover.