Browsers.

Browsers release history.
Browser popularity.
Browser performance.

Browsers release history.

https://wiki.mozilla.org/Releases: Firefox Releases.
http://en.wikipedia.org/wiki/Firefox_release_history: Firefox release history.
http://en.wikipedia.org/wiki/History_of_Firefox: History of Firefox.
http://www.opera.com/docs/history/: Opera version history.
http://en.wikipedia.org/wiki/History_of_the_Opera_web_browser: History of the Opera web browser.
http://en.wikipedia.org/wiki/Safari_version_history: Safari version history.

Browser popularity.

http://caniuse.com/usage_table.php: Browser usage table, based on data from StatCounter GlobalStats.

Browser performance.

http://arewefastyet.com/: Tracking performance of popular JavaScript engines.
http://jsperf.com/: JavaScript libraries performance.