1 1and1.com (0) -
calls themselves the world's largest hosting service. "What does that have to do with us?" I say? Well, there are some of our subscribers who use them. They may not know they use them, because as a large hosting company, they also host email servers for small, medium and large businesses who host their entire operation on 1and1 servers.
They are so large that they have become very hard to work with, or more specifically, get help from, especially if you are not one of their customers. They blacklist IP addresses, which they are now doing to ours, and there's no recourse for us to unlist ourselves. They offer no contact method other than email, and if email is blocked, tough luck...
To read about this, visit this blog (see the Update at the bottom about his solution, which isn't available to me) 1and1-Refuses-email
Like PSMTP.com, they have earned my disdain. For example, today (7.14.09), they have caused a backlog of over 150 emails waiting for delivery. AND, the saga continues. They continually have failed deliveries and it seems it will never stop. Maybe it's just us. If you own a small domain, and your email isn't coming through, find out if your email is handled by 1and1.com. You can do this by visiting http://networksolutions.com/whois/ (more information)
or
http://www.internic.net/whois.html (simpler, but less information).
Enter your domain name in the box provided. If the NS or MX pointers show 1and1.com or schlund.nnn, you're going to have problems.
As in other cases like this, I strongly recommend you get a personal/private email address that doesn't use 1and1.com (or PSMTP.com). Some of those services include gmail.com, netscape.net, aol.com (same as aim.com), hotmail.com, yahoo.com, etc... OR, and this would be better for everyone going forward, If You Are A 1and1 customer, Please contact 1and1 and have them remove ourldsfamily.com from their blacklists.
So, a word to the wise who aren't already using them, if you see this logo,
RUN!
Update: All domains that use this have been unsubscribed from our email server and when new domain clients subscribe, they are notified of this page, and then unsubscribed after a few days if they don't respond. Problem solved? No, just deferred...