You can't just pick out a single site and draw a conclusion that their users are representative of the general population - The percentages will vary from site to site and also from country to country.
What's the best source for browser usage stats?
http://www.impressivewebs.com/browser-usage-stats/
Browser Stats
http://www.upsdell.com/BrowserNews/stat.htm
The best stats for a site are the stats gathered for that particular site: and even these are skewed by caching and faulty browser-detection. For example, consider Kerry Watson’s Browser Statistics page: this page uses three different hit counters whose reports should be comparable; but they are not, in part because of faulty browser detection.
Bottom line: use statistics with extreme caution.
W3 Counter
http://www.w3counter.com/globalstats.php
StatCounter
http://gs.statcounter.com/
Usage Share of Web Browsers (Wikipedia)
http://en.wikipedia.org/wiki/Usage_share_of_web_browsers
As can be seen it is almost impossible to come up with actual usage levels for each browser - and it is easy to find a site with stats to support your argument or your favorite browser.
The "most popular browser" is important probably only for the marketing people in Microsoft/Google or Mozilla. For the average user they choose a browser that they like (works the way they want to work).
Hopefully close competition between the browsers will promote innovation and fresh features as each company tries to invent a better mousetrap. While I don't use the browser "Opera" - it is nice to see they can innovate from "behind" (in terms of market share), and the claims that several ideas that were introduced first in Opera have since been adopted by the "Big 3".
