IPad – Reformatting After Magnification

I’m a new iPad user and am trying to figure out what controls the reformatting of the screen after you magnify. It seems that while in a few apps (email for example), the screen will automatically reformat after you magnify. However, in most apps (web browsing in techrepublic.com for example), the screen does not automatically reformat and you end up having to scroll back and forth to see all the text.