Will Ymail lure you to Yahoo! Email?  For that matter, will Rocketmail? Starting this morning, Yahoo! will be opening up ymail.com and rocketmail.com email domains for users.  Why?It’s obvious that if you wanted to get the email address john@yahoo.com, you couldn’t. Saturation has meant that if you want to get an email address at Yahoo!, or for that matter, Gmail, you frequently have to resort to adding numbers or other such differentiating characters.  What a pain, right?Today, Yahoo Inc. will