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The document located at <http://mobile.cebit.de/> was successfully checked as mobileOK®. This means that the resource in question passed all the tests defined in the W3C mobileOK Basic Tests 1.0 specification.
If you are the author of the Web page, you may wish to identify your content as mobileOK conformant. There is more than one way to claim mobileOK conformance, detailed in the Claiming conformance section of the W3C mobileOK Scheme 1.0 document. Here are two possibilities:
Images and/or image objects must be delivered in an appropriate format and dimensions so that they can be retrieved and rendered by most mobile browsers. mobileOK requires that all images and rendered objects be either GIF or JPEG images.
The source of the messages in this category is to be found in the HTTP headers that were sent along with the page. They are most likely due to the Web server configuration for static files, or the way the server-side scripts are written for dynamic content. Making sure that HTTP headers are correctly defined is essential in a mobile context with a usually low bandwidth and high latency.