Konqueror is a WebBrowser brought to us by the KDE project. It is not as featureful or 'good' as Mozilla in most ways, but it is also a whole lot faster. This is probably why Apple chose to use KHTML, Konq's rendering engine, for their new web browser Safari.
Konqueror seems to start up and respond a lot faster than Mozilla on a slow machine. (Mine is 333MHz.) An annoying thing about Konqueror is that continues to download the images on the page after you've stopped it downloading the page itself.