I haven't tried this Safari 5 feature yet, but it sounds very similar to a feature that is also already on the iPad version of Safari and other iPad apps that m

I haven't tried this Safari 5 feature yet, but it sounds very similar to a feature that is also already on the iPad version of Safari and other iPad apps that make use of the web view API. On the iPad, if you double tap on the text area, the view will zoom in just enough so that the horizontal span is as wide as the main text region. But a big difference on the iPad is that the original presentation is not modified, just zoomed in.