While it is very easy to find services that will send your email for you it is imho difficult to find services that will allow you to send and receive bulk email. When you give users of your service custom email addresses, you can start to do really cool things, like have users reply back to comments via email.
I inquired about their policy, and they pretty much treated me like I was found under a rock. In spite of us running a clean site (I showed the the URL for the newsletter page, and our clean multi-RBL lookup), and they still wanted me to agree to this BS terms-of-service page with such unreasonable terms I dropped the entire idea.
Which is a shame, since the current provider really sucks, from a support perspective, but they've never been unreasonable about, you know, using the internet to send mail to a bunch of people at once.
Between this attitude and rabid mail admins with unreasonable RBL policies (like flat-out rejecting a message for being listed on only 1 of ~40 or so public RBLs -- one that demands money for immediate delisting), I've witnessed a slow Balkanization of the internet over the years.
If for some reason bulk mailing providers do not suit you it cheaper to have a separate machine/IP address for sending such emails than having to deal with important emails not coming through because somebody blacklisted your IP address although he subscribed to the mailing list.