By looking at the average number of page views per user per month and the average pageloadtime, I was able to develop an estimate of the total hours the US population wastes each year due to slow web application performance.
The score represents how well optimized the page is for speed, but does NOT measure the actual loadtime. (The real loadtime, of course, is what users experience.) So, slow servers or connections or content from other sites (like third party ads or widgets) can kill performance even on a site that gets a great score.