If you built a website around 2015 and optimized it with the tools and thinking of that era, here’s something you need to hear: the rulebook has been rewritten. Not once — six times over.
The strategies that once moved the needle — stuffing pages with keywords, building link networks, launching a mobile “m-dot” subdomain — don’t just underperform today. Some of them will actively hurt you. Google has spent the past decade rewarding websites that serve real people, and penalizing ones that try to game the system.
Here’s what changed, and why it matters to your site right now.
1. Mobile-First Indexing (2015–2018)
In 2015, Google fired a warning shot called “Mobilegeddon” — a ranking update that punished sites with poor mobile experiences. By 2018, they completed the transition: Google now indexes and ranks your mobile version first. Your desktop site is secondary.
If your site still isn’t responsive — if users have to pinch and zoom to read your content — you’re not just losing mobile visitors. You’re losing rankings across the board.
2. RankBrain & Machine Learning (2015–2019)
In 2015, Google introduced RankBrain, an AI system that interprets the meaning behind search queries rather than just matching keywords. It was the beginning of the end for exact-match keyword stuffing.
By 2019, a follow-up system called BERT allowed Google to understand context, nuance, and natural language at a deep level. Writing the same keyword 15 times on a page no longer signals relevance — it signals spam. What matters now is whether your content genuinely answers what a searcher is trying to accomplish.
3. E-E-A-T: The Rise of Content Authority (2018–2022)
In 2018, a major algorithm update — nicknamed “Medic” — elevated a new set of signals: Expertise, Authoritativeness, and Trustworthiness (E-A-T). In 2022, Google added a second “E” for Experience, reflecting that first-hand knowledge matters.
This is especially critical for any site covering health, finance, legal topics, or advice of consequence. Anonymous, generic content lost ground fast. What replaced it: named authors with credentials, cited sources, brand reputation signals, and content that demonstrates real-world experience. If your “About” page is vague and your articles have no byline, this one’s for you.
4. Core Web Vitals & Technical UX (2020–2021)
In 2021, Google formalized a set of performance metrics called Core Web Vitals, built around three questions: How fast does your main content load? How quickly can users interact with the page? Does the layout jump around while loading?
For the first time, technical page performance became an explicit ranking factor — not just a user experience nicety. A slow, janky website, even with great content, now faces a measurable disadvantage. If you haven’t audited your site’s performance scores recently, Google’s free PageSpeed Insights tool will give you a rude awakening.
5. Helpful Content: Human-First Writing (2022)
In 2022, Google launched its Helpful Content Update with a clear target in its sights: content written for search engines rather than for people. The kind of content that hits every keyword, follows every on-page SEO formula, but says nothing useful to an actual human reader.
This was a philosophical shift. Optimization itself wasn’t devalued — but optimization divorced from genuine usefulness was. Sites built on thin, templated, or AI-generated filler took significant ranking hits. The question Google now asks is simple: if search didn’t exist, would anyone find this content worth reading?
6. AI Overviews & the Zero-Click Era (2023–2025)
This is the one that changes everything. Google now answers many queries directly in the search results — no click required. And with AI Overviews rolling out broadly in 2024, that trend has accelerated dramatically.
Ranking #1 no longer guarantees traffic. The goal posts have moved: the new prize is being cited as a source inside AI-generated answers. That requires authoritative, clearly structured, trustworthy content — which loops back to every point above.
The Thread Running Through All Six
A decade ago, SEO rewarded sites that understood Google’s algorithm. Today, it rewards sites that serve their readers well enough that Google’s algorithm has no choice but to take notice. If your strategy hasn’t changed since 2015, it isn’t just outdated — it’s working against you.
The good news: the same update that fixes your mobile experience helps your Core Web Vitals. The same investment in authoritative content helps your E-E-A-T signals and your chances of appearing in AI citations. The improvements compound.
Start with one. The best time to update your SEO thinking was ten years ago. The second best time is now.