How many web browsers do you run? If you're like me, you regularly use Firefox, Internet Explorer, Chrome and Safari. Each of those browsers, of course, has its own underlying rendering engine: Gecko (in Firefox), Trident (in Internet Explorer), and Webkit (in Chrome and Safari). Today, a Japanese startup called Lunascape has released an alpha version of its Lunascape browser, downloadable here, that allows you to switch between all three of these prominent rendering engines. The company says that the Japanese version of Lunascape has been downloaded 10 million times and touts it as the fastest browser available. Is it?

In October, Mozilla witnessed a surge in Firefox 3's market share as it continued its plan to decommission Firefox 2 -- and the Gecko engine that powered it -- before the end of December.

For two weeks in October, Firefox 3 claimed 20% market share, something that web metrics company Net Applications predicted might happen within a month of the new version's June release. Stalled growth, and Chrome's appearance caused some backslide, but Firefox 3's pulse is getting stronger.