With the inclusion of certain new anti-spam techniques, I have temporarily suspended the ban on gmail, yahoo, and other such common addresses so that people can use them for registration.
That being said, I can only caution you against actually using such public services. Without pointing a finger at any particular service, time and time again, each of these public and high-profile services has been proven to be hackable and unsafe for personal communication.
If the new anti-spammer measures don't keep spammers from registering using those addresses, I will have no choice but to go back and close that loop again.
Please understand that I'm not doing this because I hate said services, or because I want to make life here difficult for new registrations. We just have to do whatever is necessary to protect our server and site from such vermin.
Thanks for your understanding.
Wayne