Penguin

Mozilla is an OpenSource project mainly working on a WebBrowser which is quite clearly established as the WebBrowser to beat. It aims for standards compliance, and has popular new features such as tabbed browsing and popup blocking. The next generation Mozilla browser, dubbed MozillaFirefox, is much leaner in terms of resources, and has a more responsive GUI.

The Mozilla project also serves as the umbrella for many subsidary projects:

See also MozillaNotes.