emotion cons put in e-mail? (the faces not texts used as faces)?

Enable compose in color and graphics, in options on the mail page. That's all there is folks.

When writing an e-mail on Yahoo! Mail, there should be a toolbar that allows you to format your messages, e.g. underlining text, indenting, highlighting.

One of those items on the toolbar is the emoticon one, allowing you to insert emoticons. It looks like a smiley face with sunglasses. Click on it, then a drop-down menu will show, so that you can choose what kind of emoticon to insert.