All of these approaches are used to take advantage of the email deliverability rates of large reputable companies that send lots of email. Paypal is a new one,

All of these approaches are used to take advantage of the email deliverability rates of large reputable companies that send lots of email. Paypal is a new one, but Hotmail and Facebook have in the past been used for similar things. With Hotmail, you could define a custom "I've changed my email address" message, which would contain your spam message, and then it would send it to up to 5,000 "contacts" for you with near-100% deliverability. Some people automated this, and with that they were able send millions of messages per day. I haven't looked recently, but Facebook's "invite friends" feature has been used similarly in the past.