The email addressed got either posted here(no longer supported) by its owners or from public internet sources.
PROTECT YOURSELVES FROM SPAM:
Our reponsability: Spamers are known to harvest e-mail addresses from guestbooks or lists. This login with password is to protect your e-mail address from automated e-mail harvesting.
Your responsiblity: Don't run other Andrists into SPAM troubles by registering them with Internet Services including greating cards services etc. It's further probably most worthwile to spend a few dollars a year to have an always updated virus protection on your PC. This avoids all your friends addresses stored on your PC being abused for Spam based on virus.