MiniWeb is a small generic web browser. It lets you configure the user agent string it sends to websites, so that these sites think you have a browser that you don't. This is useful when testing websites against various mobile browsers.
MiniWeb is also handy if you want to watch news tickers, sports scores, weather reports and such things on a small window, but not in your main browser. The formatting of some websites for mobile clients (phones) is sometimes more convenient for this purpose.
Finally, if you can't afford one of those fancy new web phones, but you want Google to think you have one, just use MiniWeb and set the user agent to the latest fashonable expensive gadget.