Shoutbox

I have not visited the site, but it sounds like your friend was probably using the site to check who has blocked them and it does that to advertise the service before changing the user's nickname back to normal and signing out.

Block checkers do not work properly any more and are often very risky as it involves giving your password to third parties who may not necessarily be whom they appear to be. If your friend is lucky it may just be advertising and that is it, if he is not then he has given his password to someone who will attempt to hijack his Windows Live Passport.