Firefox falters, falls to record low in overall browser share:
Firefox’s user share on all platforms — desktop and mobile — has plunged in the last two months as its desktop browser continued to bleed and its attempt to capture users on smartphones failed to move the needle, new data shows.
Huh. Can you think of anything that might have happened about two months ago that might have angered a large number of its users and caused them to change browsers?
Correlation is not causation, but a sudden shift might not come just from the release of the iPhone 5S.