Basics
Your friend list is located next to the 'Send' button. If your friends username is bold on your friend list, it means the user is online. If it is not, it means they're offline. You can chat with anyone on your friend list, as long as they're online, even if they're not in the same scene as you.
Adding Friends
It's easy to make friends in Vivaty. Sure, your virtual good looks help, but with a little charm and wit, and by right-clicking on a potential buddy, you can add friends to your list. Don't get too carried away, though. Nobody likes the guy with 10,000 people on their MySpace page. Nobody can be that popular, can they?
Adding a friend means they'll see you when you come online, and also that you can more easily join them. You can also restrict access to your scene just to friends, if you're really super exclusive.
Removing Friends
Sometimes, friends go rogue. If you find yourself wanting to remove someone from your friend list just click their username in the friend list section and click remove.