1) yes, that thread is related top the current version of Power Messenger, but none of the ideas in that thread are supported or tested. They may or may not work.
2) That tutorial is geared to a subscribe / unsubscribe solution that uses only the email address, but again it is unsupported for use with Power Messenger.
In the development of Power Messenger, they went with a standard Security Assist user login using a Email and Password. if you wish to see a version that does not use a standard login login system, please feel free to post your suggestion to the suggestion page: