20 Jun 2012
It’s going to be a busy two weeks. I’m in London right now, meeting with some of our partners, then off to talk about mobile at USI in Paris on Monday, then straight to Santa Clara to sit on a Velocity panel about performance tools on Tuesday.
Now that I’ve fulfilled my self-pimping obligation, I want to take a minute to revisit some of my favourite sessions from past Velocity conferences. Recently I read somewhere that we tend to distrust information that’s more than a year old, but I have to say that I find these slide decks, some of which are three whole years old, still interesting and relevant today.
Paul Roy, Alex Polak, Gregory Bershansky
MSN shared some case studies that showed how speeding up load time affected page clicks. I live for these kinds of case studies, so I was happy to learn that:
- In an experiment with implementing synchronous jQuery load, they experienced a +0.5% increase in search clicks and page clicks.
But what I thought was particularly interesting was the case study around delaying ad loading. They experimented with delaying the loading of a major ad by 1 second, which improved the time to onload by 500ms. As a result, they saw an increase page clicks and views, but a 15% dropoff in ad clicks.
Obviously this kind of ad performance hit isn’t viable for a site that relies on CTR for revenue, but what grabbed my attention was MSN’s takeaway from this exercise:
My favourite thing about this session was that, rather than being scared off by the initial 15% hit to CTR, Microsoft persists in looking for the sweet spot that yields faster load time without hurting advertisers. This improvement may end up just being a hundred or so milliseconds, but the message here is that it’s a goal worth chasing.
Julia Lee, Senior Director of Engineering, Yahoo! Mail
With almost two billion page views a day, the cumulative effects of latency can hit Yahoo mail hard. They found that 73% of their overall latency was due to ads. No surprise when you look at how convoluted an ad’s server call can be:
What does this convolution add up to, performance-wise? Julia shared that in the old days, before redirects, the average ad experienced about 464ms of latency. Over time, that number grew to 2.7 seconds.
If you’re in mobile web development, this slide deck is a must-see. Starting at slide 51, Maximiliano gives an impressively thorough breakdown of optimization tips, from handling images to deferring content. This slide is my favourite:
In this session, Imad shared some KPI data,back when such information was still hard to come by, including this graph showing that speeding up a page by just 4 seconds decreases abandonment by 25%:
This was a great presentation that demonstrated (to many of us for the first time) the human factors side of web performance. For example, Stoyan showed that there’s a distinct difference between perceived speed and actual speed. When it comes to web performance, this difference works against us:
There were a handful of messages that were threaded throughout many of the presentations and discussions at Velocity 2010. The relationship between performance and the bottom line was one of them. Sean presented some visuals that hammered these points home. Among other things, he showed how, as latency increases, conversion rate drops:
Sean also showed the long-term effects of poor performance: a poorly performing website suffers not one but two waves of abandonment, as users spread the word of their poor experience and drive other users away from the site.
In the last part of his session, Sean offered a realistic step-by-step plan for dev/ops folks to measure performance and outcomes in their organization. He said that if you create only one graph for your site, it should be one that looks something like this, which shows the direct impact of page load on conversions:
Eric Schurman and Jake Brutlag
There were many cool things about Velocity 2009. One was the presentation of so much brand-new data about the relationship between page speed and business metrics — often done by deliberately slowing down pages, which was considered a pretty radical idea. For many people, this connection, which we take for granted today, was a revelation. Another cool thing was the research partnerships, like this one between Amazon and Google. Definitely worth a watch.
More groundbreaking research. AOL found that visitors in the top ten percentile of site speed viewed, on average, 7.5 pages per site visit. Visitors in the bottom ten percentile viewed just 5 pages per visit.
This is a seminal piece of research. Back in 2009, Shopzilla became the poster child for web performance when they shaved almost 5 seconds from their page load times and increased revenue by 7-12%.
It’s been fascinating to note the evolution of themes from year to year, and to follow the ever-deepening nuances of performance. I’m looking forward to seeing what Velocity 2012 holds.