It appears at the Ajax Experience conference going on this week, Yahoo! has released a add-on for Firebug which analyzes your page for possible performance issues.  In other words its figuring out why your page may be slow, or in Yahoo terms YSlow.  Its cute, it isn't it.

Judging by my initial report card for this site I have a fair bit of work to do.

And in a smart move to educate the developer as well as spread the meme, each of the bulleted items links directly to one of Yahoo's Thirteen Simple Rules for Speeding Up Your Web Site.

Although, I've only been using it for a little while, I can foresee YSlow as becoming a handy tool for web development.