Hotmail has a spam problem
Allow me to make that more sensational: Hotmail has a bad spam problem. Despite everything that Microsoft has said and done about being against spam, their Hotmail service is the source and the facilitator of an increasingly large amount of spam email.
As noticed most recently by Chris Linfoot in a series of blog entries (How to abuse Hotmail and get away with it and More on Hotmail and Personal Addresses), Microsoft will allow more or less anyone to register a 'Microsoft Personal Address'.
A 'Microsoft Personal Address' is your own domain name. Through Hotmail, Microsoft provides all of the services your domain needs: DNS, incoming mail, a URL forwarding service, and even outgoing email through Hotmail's own mail machines. In other words, about eight and a half yards of the full nine yards of spam support.
Worse, Microsoft provides no mechanism for people to report spam related to these domains. As Chris Linfoot has discovered, even complaints about spam email sent from Hotmail's own servers will be rejected by Hotmail with a form letter claiming that they are not responsible for any of this because it doesn't involve a '@hotmail.com' mail address.
Practically any other ISP in the world would be publically pilloried for spam support this blatant, and several of them have been. But for some reason Microsoft and Hotmail get a free pass, despite the parade of various sorts of advance fee fraud spams that constantly emanate from Hotmail's mail servers.
Locally, we have dealt with this problem by refusing any email message
from the Hotmail mail servers that doesn't have a
MAIL FROM of
hotmail.com. In at least a year of operation, we have yet to have a
user complain that they aren't getting email, and we routinely reject
200 such messages every week. Unfortunately this is not something that
leads to a real solution, since it does almost nothing to get Hotmail's
attention or make it painful for them to continue doing it.
Chris Linfoot has also had to do this. (And shortly after he put the rule into place, it started blocking spam. Not surprising; at around 200 a week, that's 28 spam messages a day from Hotmail's servers.)