Apple has been employing a policy with its app store that disallows duplication of existing functionality, though that would now seem to be defunct with the introduction of new web browser options. The four new browsers added so far are all based on Apple's Safari developer kit, so the rendering engine doing the work underneath is essentially the same as that of the default browser. New functionality has however been added to the new browsers, such as increasing browsing window size (Edge browser) and something close to tabbed browsing (WebMate). While it isn't expected that any of the major players will get involved iPhone browsers, it should be worth keeping track of what is available and whether Apple updates its own browser with improved functionality at some stage.