You need to have an email invitation from the organizer or a link to a gift exchange in order to join an exchange. Once you have your invite, click on the link that you received from the organizer (either by email or a link from Facebook or Twitter). Simply follow the instructions on the page to RSVP. If you have not established an account, you will need to create one to RSVP. Multiple accounts may use the same email address, however, each person needs to have their own unique user name and password for their account.