“YSlow analyzes web pages and tells you why they’re slow based on the rules for high performance web sites. YSlow is a Firefox add-on integrated with the popular Firebug web development tool. YSlow gives you:
- Performance report card
- HTTP/HTML summary
- List of components in the page
- Tools including JSLint
“YSlow analyzes any web page and generates a grade for each rule and an overall grade. If a page can be improved, YSlow lists the specific changes to be made.”
It’s an interesting tool, but you’re going to get an “F” or no higher than a “D” unless you “Use a Content Delivery Network“, “Gzip components“, and Configure Etags.
Chronicle of Philanthropy - 64 (D) areas of concern: Use a Content Delivery Network, Add an Expires Header, Gzip components, and Configure Etags
NonProfit Tips - 63 (D) areas of concern: Use a Content Delivery Network, Add an Expires Header, Gzip components, and Configure Etags
Robert Scoble - 57 (F) areas of concern: Use a Content Delivery Network, Add an Expires Header, Gzip components, and Configure Etags
Microsoft - 47 (F) areas of concern: Make fewer HTTP requests, Use a Content Delivery Network, Add an Expires Header, Gzip components, and Configure Etags.
ASPCA - 45 (F) areas of concern: Make fewer HTTP requests, Use a Content Delivery Network, Add an Expires Header, Gzip components, Put CSS at the top, Move scripts to the bottom, and Configure Etags.
Seth Godin - 43 (F) areas of concern: Make fewer HTTP requests, Use a Content Delivery Network, Add an Expires Header, Gzip components, and Configure Etags.
Yslow (from WebProNews)