Did you know that without anything special going on, telephone numbers on websites are picked up by the iPhone (and iPad and probably all the other mobiles) web browser so they can be clicked. This brings up a call/cancel option.
I know there are proper ways to link to phone numbers (iPhone telephone hyperlinking for instance) but it just works anyway!
The reason I came across this was because an eagle-eyed client spotted an invisible telephone number (eh?) when browsing his site on an iPhone. Techie bit coming which you can skip past if you aren’t that way inclined. The phone number was dark grey on a white background on ‘normal’ browsers but all the website’s links were set to be white when untouched or visited. Thus the iPhone magic of making a phone number into a link, using the styling from the website made the link white on a white background. I simply gave the phone number a different class and some appropriate style for links in that class et voila – links that are visible on the iPhone and not links on ‘normal’ devices.
Well I thought it was interesting anyway…