Email confirmations going to junk / not arriving

We are beta testing a new site with a handful of new member and have noticed a problem with anyone that has a Microsoft email account (Hotmail, MSN, Live, Outlook, etc). It seems that Microsoft are classing our email confirmations as junk and in some cases they are not even delivering them to the junk folder which is preventing a lot of people from joining.

It's a brand new site on a dedicated server with very few members at present, so I don't think it's an issue with people reporting our emails as spam. I've tried changing the title and the content of the email (stripping out the headers etc and making it plain text) to see if anything in there was triggering the spam filters, but this doesn't seem to make a difference. Has anyone got any ideas?

I had the same problem.  I had to join their developers program for hotmail and add a script to my site.

Once I did that, my emails went thru.

It took a couple weeks to get it cleared up.

I've found that some mail servers treat the default email template text as potential spam.  Removing the BoonEx blurb at the bottom usually makes a difference.

The day nobody uses Hotmail anymore will be a nice day in my book.