Your right to invite others are usually referred to as an "invite". We're not handing out invites anymore, please read announcements.
Invites are now given once every 180th day. You have to be at least PU to gain invites, with at least 30GB downloaded, and ratio above 1. You will recieve max 2 invites, if you do not use them.
You may see how many invites you have available, by visiting your "profile"-page, and look for "invites" just after the number next to "Gitt/Tilgjenlig" (Used/Available). To invite someone, select "Tilgjenglig" (Available), type in the e-mail address of the person you're inviting, and click "Inviter". A confirmation will be sent to the e-mail you just typed in, and the person will be given 3 days to confirm it, in order to activate the account.
If an invite is not confirmed within 3 days, it will be deleted by the system. You have the opportunity to manually delete the invititations you've given away, by visiting your "profile"-page, and choose "Gitt" (Used) under "invites". A table will show you all invites you've given. Choose "Slett" (delete) to delete an unconfirmed invite. All deleted invites will be given back to you as an extra invite, so don't be afraid to delete them.