You should not use QWebView, and especially not the zoomFactor() for touch based browsing.
We have not had the time to do proper documentation about it but touch-based browsing is quite different from the regular browsing.
For touch-based browsing, you generally use this:
QGraphicsWebView
Frame flattening
Tiling
zoom by scaling the QGraphicsWebView
Some more info there:
"http://gitorious.org/light":http://gitorious.org/light : basic browser for touch screen
"http://gitorious.org/yberbrowser":http://gitorious.org/yberbrowser : an interesting browser for the N900
"https://bugs.webkit.org/show_bug.cgi?id=41465":https://bugs.webkit.org/show_bug.cgi?id=41465 the bug report about improving the documentation regarding those feature. A first patch is already available.
Feel free to comment on bugzilla if you have ideas to improve the documentation further. If you have more questions, do not hesitate to ask them here on the forum.