@SimonHearne
The State of
Third-Party
Tag Performance
Simon Hearne
Web Performance Consultant
We pitch ad blockers on speed
Experience a cleaner, faster web
AdBlock Plus
Opera will speed you up on the web and make sure ads don’t distract you from what matters
Opera
..control over ads and tracking technologies to speed up page loads
Ghostery
Users want speed
Top Motivations for Using an Ad Blocker:
- Too many ads (48%)
- Irrelevant ads (47%)
- Ads are intrusive (44%)
- Viruses / bugs (38%)
- Ads take up space (38%)
- Improve page load speed (33%)
- Avoid video ads (29%)
- Privacy concerns (26%)
- Preserve data budget (23%)
- Preserve device battery (23%)
Coming Up:
- The Importance of Speed
- Getting Speed Data
- Tags?
- Tag Performance
- The Impact of Ad Blockers
Data Source 1 📊
Data Source 2 📊
The Importance of Speed
Speed matters
 |
The BBC loses an additional 10% of users for every additional second it takes to load |
 |
Pinterest improved load time by 40% and saw 15% increase in SEO traffic and 15% increase in conversions |
 |
The Financial times increased user engagement by 30% when they released the new, performance focused FT.com |
Speed Correlates with Engagement
~1Bn mPulse pageview beacons - early March 2019
Getting Speed Data ⚡️
Collecting Data 🔎
Ad Hoc 🛠
- Developer Tools
- PageSpeed Insights
- WebPageTest
Synthetics 🤖
- Rigor
- Catchpoint
- SpeedCurve
RUM 🥃
- Analytics?
- APM
- mPulse 👍
Data Points
A Willing Victim
Gotchas 1/3
The Timing-Allow-Origin response header specifies origins that are allowed to see values [..] which would otherwise be reported as zero due to cross-origin restrictions.
Gotchas 2/3
all content loaded from cross-origin IFRAMEs (and below) are completely hidden to ResourceTiming.
Cross-origin IFRAME opting-in to sharing ResourceTiming data
Gotchas 3/3
Ad Block detection on one national publisher,
with a narrow demographic.
Tags?
Tags!
1/4 of web pages have
>90% third-party requests
Tags serve business goals 💵
- 💹 Measurement & Analytics
- 🧪 Personalization & Testing
- 💬 Comments & Live Chat
- 🏷 Tag Management
- 💸 Ads & Retargeting
"Who put Facebook on the site?!"
Tags can get out of control 😱
- 352 Requests
- 147 Domains
- 2,300kB (1,700kB tags)
Tag managers are enablers
Ad Networks are greedy
So what?
¯\_(ツ)_/¯
Tag Performance
What's the Risk?
SPOF
What's the Risk?
OnLoad SPOF
Lucky they're always fast, right?
What's the Risk?
Interactivity
The Impact of Ad Blockers
Positive, right?
A simple test
What about the wild?
Results
8.98% pageviews with ads blocked (n=50M)
| Metric | With Ads | Without Ads | Difference |
|---|---|---|---|
| Page Load Time (ms) | 6,130 | 4,600 | -25% |
| Time to Interactive (ms) | 5,480 | 4,260 | -22% |
| LongTasks Time (ms) | 1,270 | 241 | -81% |
| First Input Delay (ms) | 86 | 8 | -93% |
| Page Size (MB) | 2.69 | 1.99 | -26% |
| Bounce Rate | 68.8% | 67.0% | -2% |
| Time on Site (s) | 410 | 708 | +72% |
| Session Length (pages) | 2.80 | 4.41 | +58% |
| JavaScript Errors per Page | 1.92 | 0.18 | -91% |
Conclusions
- Third-party tags are pernicious
- Ad Blockers significantly improve performance
- Users with Ad Blocking enabled engage more
Thank you 🙏
- 📧 simon@hearne.me
- 📣 @SimonHearne
- 🌎 simonhearne.com
simonhearne.com/presentations/ad-block-perf/
The State ofThird-PartyTag Performance
Simon Hearne
Web Performance Consultant