Just to add to above points... - there is a companion called YSlow https://addons.mozilla.org/en-US/firefox/addon/5369 for firebug this is from Yahoo! would identify the leaks in the application/site and helps you to optimize the same.
Related info: Yslow FAQ http://www.google.com/url?sa=t&ct=res&cd=2&url=http%3A%2F%2Fdeveloper.yahoo.com%2Fyslow%2Ffaq.html&ei=2M_MR6T5Kpus6wO1wbX-AQ&usg=AFQjCNGkGqEsMWUtcwgXZUeUhy0oYU2IRA&sig2=_AUwDGxulBXFBtqvnYrK5w> - And also firebug will not go with Gmail, so you need to disable it for Gmail. -- Thanks & Regards, Sumanth Krishna. A Blogs: http://sumanthtechsavvy.blogspot.com/ http://yourway2health.blogspot.com/ TwinclingCommunity: http://www.twincling.org/node/209 http://www.twincling.org/node/204

