Have you seen YSlow? It is a Firefox plugin that extends Firebug’s functionality to show some interesting information, such as page load times, and the heaviest parts of the site. You can use the information gathered to increase performance on your sites. Here’s an 8 minute video presentation on YSlow by Jeremy Zawodny, who was at Yahoo! when I was there. BlitzMetrics.com, which admittedly a work-in-progress, scored only a 64. Humbling, as are the scores of many of the sites that we know and manage. If you already have Firebug and like it, then you’ll love Yslow.
I said “suck” above to get your attention. There are many ways to suck– your product or service sucks, your design sucks, your customer service sucks, or whatever. But you should never suck because your site loads slow or has coding issues.
Update: Perhaps the most common culprit we see that is an easy fix is to not compress images. That will often balloon the page to 1 MB.