We ignore IE 7 users at our peril. At the time of this writing, IE 7 has 15% market share. This doesn’t sound like much, until you translate that number into 15 out of every 100 living, breathing human beings who come to your site and are rebuffed by its poor usability.
No two performance tests give the same results. To illustrate, I put a high-traffic site, Target.com, through its paces on a handful of commonly used tests — Gomez, Keynote, HTTPWatch and Webpagetest — to see how it performs.