You check your traffic analytics and see this massive spike on March 12th. Sessions doubled overnight. Was it the Facebook ad campaign? Did something go viral on Reddit? Or did your website finally get that backlink you've been chasing for months?
Here's the problem: Six months later, you're looking at that same spike with zero memory of what caused it. Did you document it? Probably not. Did you write it down somewhere? Maybe in a spreadsheet that nobody checks.
This is the exact frustration small business owners have had with Google Analytics 4 (GA4) since 2023. Annotations - those little notes you could add directly to reports in Universal Analytics to mark important events - weren't there. If you're still navigating the transition from Universal Analytics, I covered that in my GA4 migration guide. Google finally announced that annotations in GA4 are possible on March 20, 2025, and they work exactly like you remember: right on your reports, no more guessing games.
you're probably asking "why did my traffic spike?" way more often than you should be. Annotations won't answer that question directly - they'll help you answer it yourself by documenting what you already know happened.
What Annotations Actually Do (In Plain English)
Think of annotations as digital sticky notes for your website traffic data. When you look at your GA4 reports, you'll see little markers on the timeline showing exactly when you did something that could affect traffic.
Here's why this matters: your brain can't remember what happened six months ago. Your analytics dashboard can. Without annotations, you're stuck asking the same questions every time you see a weird pattern.
Annotations solve this by letting you:
- Mark key events: Launched an email campaign? Made website changes? Added new tracking? Mark it.
- Document marketing campaigns: When you run a promotion, add an annotation with the date range. Future you will see exactly when traffic started climbing.
- Track technical issues: Website went down for maintenance? SSL certificate expired? Note it so you don't think traffic dropped because of a problem.
- Explain algorithm updates: If Google changes how it ranks pages, note it. Helps you separate "we broke our SEO" from "Google changed the rules."
How to Add Your First Annotation
Before diving in, a quick reality check: annotations are rolling out gradually. If you don't see the feature yet, don't panic. It's coming. Multiple people reported not seeing the option when it first launched, then had access a few days later.
When you have it, here's how it works:
- Open any report with a line graph: Go to "Reports" in GA4 and pick any report that shows data over time - acquisition, engagement, monetization, whatever.
- Right-click on the graph: Find the date where something happened, right-click anywhere on the line, and select "Add annotation."
- Fill in the details: You get a title field (60-character limit), a description field (150-character limit), and the option to pick a date range instead of just one day.
- Pick a color: GA4 lets you color-code annotations, which is new and actually pretty useful. Use different colors for different types of events (campaigns in red, website updates in blue, technical issues in yellow, whatever works for you).
What Should You Annotate? (And What You Should Skip)
Here's the thing about annotations: you can create up to 1,000 of them per property. That's a lot. Like, way more than you'll ever need for a small business.
So don't annotate everything. Be strategic about it. Focus on events that actually move the needle:
Good candidates for annotations:
- Marketing campaigns: Email blasts, Facebook ads, Google Ads launches, seasonal promotions. These directly impact traffic and are worth tracking.
- Website changes: Redesigned your homepage? Launched a new product page? Fixed a broken checkout flow? These affect user behavior and conversions.
- Technical issues: Site downtime (even planned maintenance), tracking code changes, SSL issues, server migration. Downtime looks like a traffic problem but isn't.
- Content marketing: Published a viral blog post? Got featured in the media? Landed a high-traffic referring link? These cause spikes worth explaining.
- SEO changes: Google algorithm updates, manual penalties, local SEO changes, or big wins that changed your organic traffic.
Stuff to skip:
- Daily operational tasks ("updated hero image," "fixed typo on about page") - that's not what this is for.
- Minor traffic fluctuations (the normal up-and-down that happens every week).
- Everything (seriously, be selective - your charts will become unusable if you annotate every single day).
Permission Stuff You Should Know
Here's the gotcha: not everyone can add annotations. You need Administrator or Editor access to create them. Marketers, analysts, and viewers can only see annotations.
If you're in a marketing role and can't create annotations yourself, talk to whoever has access. Don't have three people adding notes on random things with no coordination - that's how you end up with messy charts.
Also worth knowing: annotations only work in the "Reports" section. They don't appear in "Explorations." If you do your deep-dive analysis there, you won't see your notes. This is a current limitation, so keep your important stuff in Reports.
Best Practices (So Your Annotations Don't Become a Mess)
Here's the thing: I've seen plenty of analytics dashboards that look like someone threw confetti at the charts. Too many notes, no system, no thought put into them. Six months later, nobody can figure out what half the annotations mean.
Don't be that person. Use a simple system:
Naming convention matters
Start each annotation title with a category so you can scan the list and know what's what:
- Marketing: For email campaigns, ads, promotions, sales
- Website: For site updates, redesigns, new pages
- Technical: For downtime, tracking issues, SSL
- SEO: For algorithm updates, penalties, ranking changes
- Event: For holidays, conferences, press mentions
Examples: "Marketing - Valentine's Day sale" or "Website - New homepage launched" or "Technical - Server maintenance completed." Keep it brief but descriptive.
Use date ranges for campaigns
If something lasted multiple days (a week-long promotion, a website redesign), set the date range instead of a single point. Future you will see the full span highlighted, which makes it easier to understand cause-and-effect.
Don't annotate in real-time
Spend 5 minutes at the end of each week reviewing what happened. Add annotations for the key stuff. Make it a ritual, not a chore.
The Real Problem Annotations Solve
Here's what I've seen happen over and over: business owner opens GA4, spots a six-month-old traffic spike, and spends the next three hours cross-referencing spreadsheets, searching Slack for "anyone remember that traffic spike in March," checking email campaign calendars, asking their developer "did we change anything around March 12th?"
Three hours later, they find the answer: "Oh yeah, that's when we launched the homepage redesign."
This is wasted time. It's wasted money because they couldn't make fast decisions without understanding what their data was telling them.
Annotations fix this by institutionalizing memory. When you create a note right when something happens, future you doesn't have to be a detective. The context is already there, attached to the exact data point it relates to.
Six months from now, you'll see that spike and immediately know: "Homepage redesign." That's the difference between asking questions and getting answers.
When This Doesn't Help
Annotations are great, but they're not magic. They only document what YOU put in them. If you annotate "traffic spike" without knowing what caused it, that's not helpful - that's just moving the confusion from your brain to your dashboard.
If you see unexplained changes, you still need to investigate. Check your email campaigns, look at your Google Search Console, review server logs, ask your web developer. The annotation is a reminder to investigate, not a substitute for investigation.
Also: if you don't have access to create annotations yet, you're not out of luck. Keep notes in a spreadsheet or Google Sheet for now, then add them to GA4 once the feature rolls out to you. Better to document somewhere than nowhere.
What YouGrow Does Differently
Here's the honest truth: most agencies don't teach clients to use GA4 annotations. They don't show you how to add them, they don't explain when to use them, and they definitely don't help you build a system for your business.
With YouGrow, you get direct access to me. I'll walk you through setting up annotations for your specific business, help you figure out what's worth tracking (and what isn't), and make sure your analytics setup actually makes sense for your goals.
No generic templates, no one-size-fits-all advice. Your business is different - your marketing, your website, your traffic patterns matter. We figure out what annotations work for you and build a process around that.
Getting Started
you could spend weeks reading every GA4 tutorial, or you could spend 15 minutes adding your first annotation right now.
Open GA4. Go to Reports. Find a chart. Right-click. Add an annotation for something you remember doing last week or last month. That's it.
You'll thank yourself six months from now when you're looking at a traffic spike and already know exactly what happened.
Questions about your analytics setup? Confused about what your traffic data is actually telling you? Let's talk.