Telephone Link Protocol
We've always been able to create links with protocols other than the usual HTTP, like mailto, skype, irc ,and more; they're an excellent convenience to visitors. With mobile phone browsers having become infinitely more usable, we can now extend that convenience to phone numbers:
tel protocol is used for phone numbers:
<a href="tel:18008675309">Call Jenny!</a>
If you'd like to create a link for SMS text messaging, that's easy enough too:
<a href="sms:18008675309">Text Jenny!</a>
sms protocol is used for text.
Many mobile browsers automatically linkify phone numbers on webpages but with the snippet above you can forcibly create phone links! Since said links don't work on desktop browsers, it's probably wise to create a JS snippet to replace spans with a given CSS class with phone links.
Providing users as many preferences as possible always puts a smile on the user's face. One of those important preferences is font size. I can see fine but the next guy may have difficulty with the font size I choose. That's why...