It is being detected as Safari and it can do pretty much anything that the iPhone browser can do. That means HTML5 websites designed for iPhones work pretty good (including stuff like geolocation, multitouch for zooming maps etc...).

Unfortunately not all websites have fancy mobile versions that take advantage of every feature that is available. Some webmasters still seem to live in the age of wap and love forcing "dumbed-down" mobile version of their site on every mobile device, which is... aggravating.