One of the most frequent complaints I hear about YSlow grades is, "Some of these performance rules do not apply for my website." Most web developers want to evaluate site performance according to their own specific design and content criteria. For example: Not all sites use content delivery networks (CDNs). With the latest release of YSlow, it becomes really easy for web developers to configure their own rule sets and get relevant grades for their pages. We've also incorporated nine new rules, in addition to the previous thirteen. The ability to create your own rule set for performance testing is a next step towards opening up YSlow for developers to create and share their own rules.
Improving page performance sometimes involves reducing page weight. Images are one of the biggest contributors to page weight for most sites. Our performance rules talk about optimizing images to improve performance. Most often, in-depth knowledge of tools like Photoshop and other design tools is required to publish highly optimized images. We've removed the pain of optimization in this version of YSlow by integrating with Smush.it. Smush.it finds all images on your web page and applies the right techniques to optimize them without visual quality loss. Developers can also download smushed images in a zip format.
The new look is designed to encourage developers to evaluate their webpage performance more closely and pay attention to small details, like making sure they've used small favicons that are cacheable. Our goal is a better, faster web experience for all.
If you have any questions or feedback, we encourage you to join the conversation on the Yahoo! Exceptional Performance group. We look forward to your continued interest and enthusiasm ? stay tuned, there's still a lot more to come.
Note: You can download this new YSlow release for Firefox here. Thanks to cancel bubble (below) for providing the reminder and the link.