Disabling Etags from affecting your YSlow score

YSlow is a great tool to quickly determine what optimizations can make your site quicker. However, Yahoo determined to include checking for ETags; if the server in question has ETags enabled, YSlow scores will be negatively affected. This should really not always be true, as ETags aren't always "bad"; if your site runs from a single server, having ETags enabled helps.

Looking for an explanation for this, I came across a comment from David C-L inside the Yahoo Developer's Blog:

• Type about:config in the Firefox address bar.
  
• look for the setting named extensions.firebug.yslow.pointsEtags and set it to 0. If the setting doesn't exist, you can create it by right-clicking and choosing "Add".
  

Now Firebug will not ignore the ETags setting on servers to determine the YSlow score.