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A client of mine had three websites hosted at BlueHost. One day they were all down. She called BlueHost and they said, "Sorry, due to a hardware failure, all of your files are gone." Forever, irretrievable, vanished, gonzo, later, sayonara, oh, yeah, sorry. Ouch.
So your site doesn't look quite like you wanted on your iPhone. This article explains some of the options to transform your WordPress site into a mobile-friendly site.