With Windows Mobile 6.5.3, sorry, Windows Embedded Handheld 6.5.3 we have the Internet Explorer Mobile 6 engine.
Although it may look nice for the one or other, the rendering, especially the zoom in and out is unusable for commercial use. The IT departments of Warehouses and Stores designed there mobile web pages for a fixed size layout of 240×320 (QVGA). Using IEM (Internet Explorer Mobile) these pages do not show well. Either they are to small to read or, if zoomed in, the user has to scroll here and there. Not very usable. Event the Fit-To-Screen option does not help.
The predefined viewport or 1024×768 may be good for browsing non-mobile web sites but I was unable to find a suitable setting for mobile sites with a fixed QVGA or VGA layout.
Here comes the tipp found at xda-developers : change the default viewport size to match your needs:
Default: HKCU\Software\Microsoft\Internet Explorer\Main Viewport Height = dword:00000258(600) Viewport Width = dword:00000320(800) Landscape optimized (VGA) HKCU\Software\Microsoft\Internet Explorer\Main Viewport Height = dword:000001e0(480) Viewport Width = dword:00000280(640) Portrait optimized (VGA) HKCU\Software\Microsoft\Internet Explorer\Main Viewport Height = dword:00000280(640) Viewport Width = dword:000001e0(480)
I assume you will find these better for commercial use than the desktop settings.
Unfortunately these settings are not used on every windows embedded device. So, you may give it a try and if it works for you, fine. I tested one device and iexplore.exe did not care about these entries. I checked with RegLoggerCE and found that iexplore.exe on that device does not query the above settings. For anyone interested, here is the log file of registry access of iexplore.exe captured with regLoggerCE: [Download not found]