I recently put together a timeline of release dates for the major browser versions because I needed a quick reference to help with browser support. The goal of this is to show how long each browser version has been around to help us make more informed decisions when deciding which browser versions to support.

Internet Explorer

• Internet Explorer 6 was released on August 27, 2001.
• Internet Explorer 7 was released on October 18, 2006.
• Internet Explorer 8 was released on March 19, 2009.
• Internet Explorer 9 was released on March 14, 2011.

Firefox

• Mozilla Firefox 2 was released on October 24, 2006.
• Mozilla Firefox 3 was released on June 17, 2008.
• Mozilla Firefox 3.5 was released on June 30, 2009.
• Mozilla Firefox 3.6 was released on January 21, 2010.
• Mozilla Firefox 4.0 was released on March 22, 2011.

Safari

• Safari 2 was released on April 29, 2005.
• Safari 3 was released on June 11, 2007.
• Safari 4 was released on June 8, 2009.
• Safari 5 was released on June 7, 2010.

Chrome

• Google Chrome 1 was released on 2008-12-11.
• Google Chrome 2 was released on 2009-05-24.
• Google Chrome 3 was released on 2009-10-12.
• Google Chrome 4 was released on 2010-01-25.
• Google Chrome 5 was released on 2010-05-25.
• Google Chrome 6 was released on 2010-09-02.
• Google Chrome 7 was released on 2010-10-21.
• Google Chrome 8 was released on 2010-12-02.
• Google Chrome 9 was released on 2011-02-03.
• Google Chrome 10 was released on 2011-03-08.

The obvious trend is that browser development is speeding up. Mozilla and Safari are on a pace of releasing a new version once a year. IE is not quite there yet. Google Chrome is virtually doing away with version numbers altogether pushing out releases at a pace of what seems to be about once every 6 weeks without really publicizing each release. It remains to be seen if this will remain specific to Chrome or if this will become a trend that other browser vendors will follow.