Propelled by the release of its Version 2.0 in October, the free Firefox web browser saw almost a 50 percent increase in use during 2006, according to one web measurement firm.

Net Applications said that the open-source Firefox browser was used by 14 percent of computers online at the end of 2006, 46 percent higher than its 9.6 percent share of the browser market at the beginning of the year.

The biggest loser was Microsoft, which also released a new version, Internet Explorer 7, last year. Despite the new version, IE's market share fell to 79.6 percent from 85.1 percent at the start of 2006.

Apple's Safari web browser rode increased sales of Mac computers to finish the year with 4.2 percent of the market, up from 3.1 percent at the beginning of 2006. Safari is only available on Apple hardware running Mac OS X.

Opera also grew its share to 0.9 percent of the market from 0.6 percent, after signing bundle deals with cell phone suppliers and game console makers such as Nintendo.

AOL's Netscape was, like Internet Explorer, also a loser. The Web browser started the year with 1.24 percent but saw its share of the market fall to 0.9 percent.