Use GripType whenever you have to type with one hand securely. Test the strength by trying to grab the device from someones hand while typing with GripType and then compare by typing with a normal keyboard.
Open a web address in Safari, text a message, search with Google, Wikipedia, Twitter, Tumblr or just open a coordinate (or an address) in the Maps app.
As extensive thumb-typing may cause repetitive stress syndrome, you should only use this app when you absolutely have to. This app makes thumb-typing less harmful, but it is still not to recommend for longer typing.