What is the most accurate estimate of web browser market share?

There's no great way to track this — virtually no way to track
installed base, for example. You can only really look at share of page
requests across a basket of sites — that's what NetApplications and
StatCounter do. Those are probably the best we have for most Western
countries. Gemius is best in Eastern Europe. There's one in Japan that I
 forget, and a number of ways to track in China. Bottom line, though, is
 that there's no very accurate way to track these — you can really only
 get an idea of trending.

Why does Chrome seem to ignore the URL when you do a search for previous webpages you've visited in the locator field?

Chrome definitely doesn't ignore the URL when you do a search. According to Peter Kasting who wrote this code, the relative weighting is URL prefix > page titles = in-page matches = matches in other parts of the URL. I have definitely experienced similar problems. The justification that Peter gives for the equal weighting of in-page and non-prefix URL matches –

"It's not really 'clear' that the page content is less memorable than the URL.  If I read a story on the New York Times, it's likely that I never even paid attention to the URL, whereas the page content is much more memorable. Part of the reason (though not all) for the omnibox design is that the majority of users neither understand nor care about URLs."

Source: http://blog.abi.sh/2009/history/…

What are the major reasons to use Firefox instead of Chrome?

I've tried to switch from Firefox to Chrome, but I can't, mainly because of:

  1. Print preview (http://www.google.com/support/fo…)
  2. Ubiquity (http://mozillalabs.com/ubiquity)
  3. FoxyTunes (http://www.foxytunes.com)
  4. All-in-One Gestures (https://addons.mozilla.org/en-US…)
  5. Opening a download without saving (http://www.google.com/support/fo…)
  6. Live Bookmarks (http://support.mozilla.com/en-US…)

(Of course, there are gesture plugins for Chrome, but I haven't found any that I like as much as All-in-One Gestures. I also like Forecastfox more than any Chrome equivalent I've found.)