When you first start using your Boxee Box(and you a first time user of Boxee) you will see this message when you click on Friends from the Home Screen. 

To add a Friend (follow) in Boxee, you will have to find them first.

• Type in the name or email address of the person you wish to follow in Search on Boxee in the Boxee website.
• Click on the name of someone you follow, and see the list of people he follows or that are following him.

After either of these actions, you will see a list of Boxee users, and next to each of them, a Follow button. Click on that button, and you will immediately start following that user on Boxee. Note that a Block option appears next to users you are already following, but more on that Friends.

Another way of following people on Boxee is by using the Find Friends option. Click on Friends > Find and give access to any of the featured email services (currently Gmail, yahoo! mail or Windows Live) to see who in your address book is already using Boxee. You can follow all of them, or select them one by one. You can also invite those who aren't using Boxee yet.

If you want to invite someone not in your address book, you can just type in an email address in the Invite people to Boxee box, and when they confirm your invitation, you will automatically become their follower.