Rich,
It is not your HOTMAIL address that has been blacklisted.
The IP address, or the IP address block, or the ISP that you used to send the reply has been black listed.
RBL stands for Real-Time Blackhole List
You sent a reply from 40.92.10.77, apparently that IP address or its IP block have been used to spam.
Three different anti-spam lists have black listed the IP address from which you sent the reply, details can be found here:
Hotmail & yahoo publish the IP address from which an email was sent, GMail does not.
Hope that helps.
-baji.