Yahoo! Developer Network Blog

Improvements in website performance are similar to improvements in energy or fuel efficiency. We make good progress yet we continue to consume more, which reverse the results of our improvements. The net effect is that optimizing performance is an on-going battle. To ring in the New Year, the Exceptional Performance team at Yahoo! (which I have had the honor to lead since July 2007 when I took over the reins from Steve Souders) would like to share our 7 Habits for Exceptional Website Performance.

1. LOFNO – Look out for number one, that is, your users. Be an advocate for your users. You do control the user experience, so don’t settle for excuses and don’t make excuses. A lot of people shift the blame towards things they don’t control. The truth is that even if it’s slow ads or the framework that’s slowing down your site, chances are there are still things you can do personally to optimize performance for your users. Has every image been optimized? Have you evaluated whether users really use that feature you pushed so hard for? Did you run YSlow? Have you set the right tone and leadership so that others know performance is a top priority for your product? Focus on what you can do, not what you can’t do. Leave no stone unturned.

2. Harvest the low hanging fruit – Find the optimizations that give you the biggest bang for your buck. If your web site has many pages, prioritize the pages. Look first at pages with higher traffic since those are the ones your users visit most. Identify strategic pages, ones that are important for the business. Create a list of performance optimizations and then prioritize that list starting with what will improve performance most. Then prioritize the same list again based on how much effort is required. Remember that removing just one image can often improve the user’s perceived response time by as much as an entire rewrite of the backend. Implement the Rules for High Performance Web Sites (aka YSlow Rules). These rules were identified at Yahoo! as the low hanging fruit for making web sites faster without compromising design or features.

3. Balance features with speed – Exceptional performance is a cross-team discipline. Our performance golden rule tells us that 80-90% of the time a user waits for a page to load is spent on the front-end. This makes the decision about what goes into the product (design, features, etc.) a major chunk of the time a user spends waiting for the components (images, JavaScript, CSS, etc.) to come down the wire. Think Yin and Yang, a constant flux of alternating forces. Designers add visual appealing elements. Product managers add functionally rich features. Engineers add flexible frameworks. All this equates to more time a user waits for your page to load. Remove images, eliminate features, compress components – all that equates to less time a user waits. Faster response time reduces site abandonment and increases usability. Less abandonment and better usability increases page views. And hey, you’ll also have a happier, less frustrated user.

4. Start early and make performance part of the process – Don’t wait until right before your product is about to be launched to discover that your product performs badly. By then, it’ll be too late. Incorporate performance into the product roadmap at design time and requirements gathering. Make performance part of the process early in the development cycle. Run performance tests at every major milestone. Every feature has a performance cost associated with it. Develop a test methodology and measure that cost. If your website requires a login, profile your most-valued users and create test accounts with the features you anticipate them to use. If your most-valued users are on dialup or broadband bandwidth speeds, make sure you run performance tests over these types of bandwidth speeds.

5. Quantify and track results – Let’s face it, we all want recognition for good work. There are lots of things we can do to improve the user’s experience. It’s more rewarding when we can quantify those optimizations. Have a portfolio of tools. Quantify performance so that it matches the experience of your users. Understand the differences between the various methodologies and tools your organization uses. If you don’t see an improvement after implementing an optimization, it could be a bad measurement methodology. There are many tools out there and different tools can show you different results. Make sure you are comparing apples to apples. Each tool has its differences, but together they can provide you a complete picture of how your product performs.

6. Set targets – Once you’ve established a methodology to quantify results, set and agree upon a target. Look at your competitors to help you determine a target. Better yet, look at the performance of pages where your users came from. From a quantitative perspective, two pages might take the same amount of time to load but qualitative research has shown us that users’ perception can vary depending on the performance of pages that load right before. Aim high and set a winning target for you, your team, and more importantly, your users.

7. Ask questions and challenge answers – Even smart people make assumptions or repeat incorrect statements. The best thing you can do is ask lots of questions, challenge answers, and if you have time verify the answers yourself. There’s no such thing as a bad question, but there are bad answers. Ask questions that give you the high-level overview. Ask questions that allow you to probe beneath the surface. Where did the information come from? How old is the data? What method was used to obtain the data? What alternative methods were considered and why weren’t they chosen? What assumptions were made? What were the drawbacks to an approach? If there was more time, what else might you have tried? Ask questions before hastily drawing a conclusion.

8. (Bonus) Run YSlow – YSlow analyzes web pages and tells you why they’re slow. Download today and run YSlow on all the pages you visit!

Happy Optimizing and Happy New Year!