[spam report] several users spam by e-mail

There are several Launchpad users whose e-mail system seems to send spam messages to all members of their address book, or all recipients whom they have sent in the past, or something like this.

https://launchpad.net/~melaniebarron
https://launchpad.net/~himura-kenshin
https://launchpad.net/~hops77
https://launchpad.net/~rus-reg

As far as I can see, all their contributions in the past year have been spam.

Furthermore there are dozens of new spam messages about university diploma in the answer section:

https://launchpad.net/~bnmdf2115
https://launchpad.net/~yzsyzshao7
https://launchpad.net/~ganghaoyi03

Please take action.