Linked phone numbers in Gmail phone dialer.

This is so cool, it just works of course. Click the number in a web page and presto the dialer pops up. Steve. 

With the ability to call phones built right into Gmail, you no longer have to get out your phone and retype a number anytime someone sends you one in an email or chat message. Starting today, you’ll see that phone numbers appear as links, like this:
Just click the number, and Gmail’s dialpad will pop up, already populated with the number 
you’re trying to call.

Click to call phone numbers - Official Gmail Blog