Very interesting thread indeed. I would like to add my thoughts on this...
1) I do not like campaigns like these that ask other people to enter 'my' email address. People do not realise that an email address is private, and I would never want my address being entered into random online forms by my 'friends'. Any opportunity for them to do this is something I frown upon. I have recently been plagued by spam mails from a website because one of my friends thought it was a good idea to enter my address. Very annoying.
2) I also dislike what I consider to be 'sneaky' tactics by websites to get your email address on to their database. If you are filling out an online form, you should have to tick a box to receive further communications, and not untick in order to not receive them. This type of sneaky behaviour is irresponsible in my opinion.
3) With particular reference to the campaign being discussed here, I have to agree with the posters who point out that speaking to customers/potential customers in this manner does not fill me with confidence. As one poster mentioned, it's as if the company is being 'run by teenagers'. It reminds me of a particular ezine I receive from an online gambling site which at times is appalling in the language used.