It is a Firefox add on extension which modifies the view of the tabs that you have opened in such a way that makes easy to you to manage them. It also has a search option to find out the tab you are looking for, if you have opened too many. So if you are one of the internet geeks and normally surf too many websites without closing the previous one, this could be really useful extension that you should download. It will look like this after you add on this extension.
Click here to download it>>Firefox Showcase<<