1. A computer-implemented method, comprising: at a portable electronic device with a touch screen display; displaying at least a portion of a web page on the touch screen display, wherein the web page comprises a plurality of boxes of content; detecting a first finger tap gesture at a location on the displayed portion of the web page; determining a first box in the plurality of boxes at the location of the first finger tap gesture; and enlarging and translating the web page so as to substantially center the first box on the touch screen display, wherein enlarging comprises expanding the first box so that the width of the first box is substantially the same as the width of the touch screen display; resizing text in the enlarged first box to meet or exceed a predetermined minimum text size on the touch screen display; while the first box is enlarged, detecting a second finger tap gesture on a second box other than the first box; and in response to detecting the second finger tap gesture, translating the web page so as to substantially center the second box on the touch screen display.