The goal of web performance optimization is to become faster and smaller: research at Yahoo! and Google found that just 10-20% of the perceived loading time is caused by the server. A few years ago we thought performance was exclusively connected to the server. However, 80-90% of the loading time incurs in the frontend. Thus WPO is more efficient targeting the frontend.

Two important weak points are JavaScript files and the sheer number of files: JavaScript loads sequentially and blocks subsequent code until each file is loaded. Hence it shouldn’t be located in the head, but in the foot of a page. Secondly older browsers, in particular Internet Explorer, will only load 2-4 files in parallel. Files queue up and get processed when it’s their turn. Therefore aggregation of files is used for reducing the number of HTTP requests.

Several international companies have conducted research or just tracked the effects of optimization.

Effects of slowness

• Amazon: 100 ms delay caused a 1% drop in revenue.
• Google: 400 ms delay caused a 0.59% decrease in search requests per user (earlier tests list larger numbers).
• Yahoo!: 400 ms delay caused a 5-9% decrease in traffic.
• Bing: 2 seconds delay caused a 4.3% drop in revenue per user.

Effects of speed

• Mozilla made their download page 2.2 seconds faster and was rewarded with an increase of 15.4% in downloads.
• Google Maps reduced the file volume by 30% and observed a 30% increase in map requests.
• Netflix enabled gzip on the server; simply by this single action pages became 13-25% faster and saved 50% of traffic volume!
• Shopzilla succeeded in reducing the loading time from 7 down to 2 seconds, whereby the conversion rate increased by 7-12%, they observed a 25% increase in page requests, they were able to retire 50% of their servers, thus saving energy costs.
• AOL observed the number of page views on several websites. While the fastest users requested 7-8 pages, the slowest only viewed 3-4.

As a cream topping Google recently announced to factor in the site speed as a parameter in web search ranking.

Eventually pages become faster, clients are happy, generate more revenue and page views, while power consumption and CO₂ emissions decrease. Saved the world, again! And if you’d like to contribute, start by checking the rules at Yahoo! A few tricks beyond that can be found in the presentation which will be translated soon.

Other conferences

The next geek meeting held in Frankfurt will be the Webmontag (Web Monday) on September 1st where I will give my presentation about canvas a short test drive.

A few days later on September 4 I have the honor of the opening talk at the Web Congress at the University of Erlangen, again about canvas, only this time a full hour.

On September 25 there’s the Best of Accessibility Symposium in Düsseldorf where I hold a workshop about hands-on ARIA (you recognize the pattern?).

On October 10-11 an internal namics conference called T-Camp is held in Basel, with my colleague Alex Stirn and me speaking about Professional Frontend Engineering.

A conference I’m looking forward to because of the many experts attending and the fair prices is the A-Tag (Accessibility Day) in Vienna, Austria, on November 21. Again I will sing praises of ARIA. This innovative technique can’t be evangelized enough! There’s no website yet for the A-Tag, but I’d recommend to book your journey well in advance to catch the inexpensive flights to Vienna. The conference itself cost only € 35 last year is free because it is sponsored by the Austrian government.

If you happen to be around, don’t hesitate to speak to me.

South by Southwest (SXSW) is a huge conference for interactive media as well as a film and music festival in Austin, Texas, March 7-11, 2008. Every year it attracts the best designers and developers, and there is an immense number of panels to choose from. Exactly 128, out of which 80 are chosen from an open submission process.

Gez Lemon and I plan to run a panel called “Get Rich, Remain Accessible,” naturally about WAI ARIA (Accessible Rich Internet Applications). Gez wrote a great article about ARIA liveregions, and I wrote that article at A List Apart, so it’s the perfect team. Together we would like to present:

1. The accessibility problems introduced by the current trend of web applications,
2. new ways to add semantic meaning, communicate importance, define relationships, and give focus to elements using WAI-ARIA,
3. how to limit the impact of these problems whilst WAI-ARIA is gaining support by user-agents, and techniques that work right now.

It would be nice if you took the time to vote for us at the SXSW panel picker application. The voting process is open until 11:59 pm, September 21. If you push our presentation to the top 80 you will ensure Gez and I actually make every effort to attend the conference as we will get free tickets for ourselves. Spread the word …

The presentation is now available for download in English or German under a Creative Commons license, so you can re-use material as long as you quote me.

Let’s face it: all of us have heard the phrase “blind people are not our target group,” either from clients or colleagues. There are a few noble souls who actually care about other people’s needs, but business is mostly about money.

So I explained how businesses lose money by ignoring accessibility. Because accessibility is not only about blind people: it’s about color blind, about old people, young people with learning disabilities, or people who are not fluent in a language. Fundamentalists will deny, but there’s also a close relation to device independence.

You may decide to ignore “a few disabled,” but you cannot ignore half of the population: accessibility is becoming a social and economic imperative.

• Andy Clarke: Royale With Cheese (PDF, 18 MB); Podcast
• Dan Cederholm: Interface Design Juggling (PDF, 22 MB); Podcast
• Dan Webb: The Mysteries Of JavaScript-Fu; Podcast
• Drew McLellan and Simon Collison: High-Noon Shoot-Out: Design vs. Implementation
• Håkon Wium Lie: One Web, Acid2 and CSS3 (PDF, 3.7 MB); Podcast
• Hannah Donovan and Simon Willison: For Example… Last FM (PDF, 1.8 MB) and Doing Local Right
• Hot Topics Panel: Podcast
• Jason Santa Maria: Diabolical Design: The Devil is in the Details (PDF, 22 MB); Podcast
• Jeremy Keith: Bulletproof Ajax (PDF, 2.1 MB); Podcast
• Jesse James Garrett: Beyond Ajax; Podcast
• Joe Clark: When Web Accessibility Is Not Your Problem; Podcast
• Jon Hicks: How to be a Creative Sponge; Podcast
• Mark Boulton: Five Simple Steps to Better Typography; Podcast
• Molly Holzschlag: The Broken World: Solving the Browser Problem Once and For All; Podcast
• Nate Koechley: High Performance Web Pages; Podcast
• Richard Ishida: Designing for International Users: Practical Tips; Podcast
• Shawn Lawton Henry: Advancing Web Accessibility; Podcast
• Tantek Çelik: Microformats, Building Blocks, and You; Podcast

Update

Thanks for the reminder, of course Joe Clark wrote detailed protocols about some sessions. Also I would like to point you to Chantal Slagmolen’s original notes — I wish all designers were so creative!

The W3C’s standards draft for Accessible Rich Internet Applications (ARIA) addresses those limitations. It provides new ways of communicating meaning, importance, and relationships, and it fills gaps in the (X)HTML specifications and increases usability for all users by enabling navigation models familiar from desktop applications. Best of all, you can start using ARIA right away to enhance the accessibility of your websites.

I held talks about the upcoming standards in Cologne and Frankfurt, which resulted in writing a blog entry about the topic that eventually became an article for A List Apart.

Update: there’s also a German translation of the article at Barrierekompass.

If you’d like to learn more I’ll be speaking at the BarCamp in Frankfurt on April 21-22, and the Infopark Internet Congress in Berlin on May 11th.