If you're using hotmail you probably won't be receiving topic notification replies, etc at the moment, i'm getting mail server bouncebacks saying @hotmail.com is blacklisted (no surprise really), so just a heads up really. I've no idea how long they will take to resolve that.
You on 1and1?
Indeed!
Yeah, they're blacklisted.
Happened a lot recently too. We've swapped our smarthosts over to Heart.
I remember Godaddy being blacklisted for me a while back too, the problem with the bigger hosts is that it invariably happens, there is too much potential for abuse.