It's come to the point where I have to disallow the use of Yahoo! emails, unfortunately. When members sign up with one, they never receive the activation email and I always get bounce back emails. Yahoo! are now appearing to
"greylist" all emails that go through their mail server. The emails are being deferred -- and it happens mostly on a shared hosting account. I understand it stops spam, but what about the legit sites out there?
Regards Jason