Update: Even more stuff! Mayur Kamat posted yet another Hangouts for Chrome update, this time showing off the new link to the Hangouts phone dialer. You can see the phone icon on the top ribbon of the main interface, accessible by pressing the green quote icon. From there you can make domestic calls for free, just like on Android, or make international calls if you have available credit. If you don't see it right away, try disabling and then re-enabling the app in Chrome's extension menu.

[Update: Dialer] The New Hangouts App For Chrome Now Works With The Desktop Browser's Notification System was written by the awesome team at Android Police.