When you receive a message on Yahoo, why would there a small smiley face

[JanetRose]

next to the sender's name on the 'from' address bar?

 

[LadyyRedd]

I'm betting it came from another yahoo address.
That face shows whether or not they are currently signed into yahoo messenger on that particular ID. If the face is yellow and smiley then they are online. If he looks like he's sleeping and grayed out, then they are not signed onto messenger.

Kimya

 

[cherylp3]

it tells you if they are online via Yahoo messinger.