Tabulous works a little differently than other tabbed browsers on offer in the App Store. When you create a tab group (lets say http://www.google.com, http://www.apple.com, and http://www.osnews.com), the “home” URL of each tab is the original URL you used to create it. That URL is ALWAYS displayed in the tab title, even if you navigate away from that URL in that tab. The idea is that Tabulous is not meant as a generic tabbed web browser (though of course you can use it that way) where you run it, you surf around, you close it. It is meant almost like a news reader or email client, where you open it, check the threads from all your newsgroups, then close it.
It is completely centered around the tab groups, as a tool designed to organize your browsing.