Common Markup Extensions
Phone numbers
To create a phone link, use:
<a href="tel:09012345678">090-1234-5678</a>
Access Keys
You can make access keys for links (so that the user does not have to select them, but can just press a number key):
<a href="blah" acccesskey="1">my link</a>
Note that the assignment of an access key is not automatically displayed, so you have to hint at the key in visible HTML as well.