Getting a lot of e-mails from appspotmail

Hello! My friend is having a problem as she always received emails from appspotmail. I asked her and she said, she signed up for an adult site which is pretty obvious since the emails always have the subject "UK Wild Girls". Enclosed with the emails are the username and password that she used after signing on the said site. I want to know where these emails are coming from. I tried clicking on any links of those emails but nothing happens. Please help.
