Very poor implementation on Apple's part (I hear this also happens on the iPad, where it makes no sense whatsoever), but there is a fix:
<meta name="format-detection" content="telephone=no" />
Source:
http://www.darowski.com/tracesofinspiration/2009/03/31/stop-iphone-from-incorrectly-auto-linking-phone-numbers/
One of the comments on that page also suggests the use of the controversial soft hyphen (­
) to prevent auto-linking of a specific number (so the browser can still auto-link other numbers on the page).
Additional Info
If you want to link certain numbers but not others, I would personally use the format-detection
meta tag to disable autolinking numbers, and then explicitly link the ones that are phone numbers:
<div itemscope itemtype="http://schema.org/LocalBusiness">
<h1 itemprop="name">Foo Co.</h1>
<dl>
<dt>Phone</dt>
<dd><span itemprop="telephone"><a
href="<?php echo ($isMobile? 'tel' : 'callto') ?>:+15555555555">
555-555-5555</a>
</span></dd>
<dt>Client ID</dt>
<dd>1234567890</dd>
</div>
The PHP snippet is there to swap out the tel:
scheme for callto:
if it's not a mobile browser. This way Skype and other desktop VoIP programs can be triggered when the link is clicked.