"As was the case last year, the bulk of Mozilla's
revenues came from a search deal with Google. That deal has now
been extended until November of 2011. As part of the deal Google
pays Mozilla a fee every time someone does a search using the
default Google Search start page that is included in Firefox.
"An interesting thing to note though is that there is not a 1:1
correlation between the user growth for Mozilla Firefox and the
corresponding revenue from Google. Baker noted in her report that,
"search revenue increased at a lesser rate than Firefox usage
growth as the rate of payment declines with volume.""