Why does the confirmation email I received from ViBi Buzz always go to the Spam folder?
That depends on how each ISP do the filtering of bulk email being received. Some will go to the Inbox folder, some will go to the Spam folder.
In order to not to have the next ViBi Buzz email go to the Spam folder, you can click "Not Spam" option, which is usually available in your e-mail application.