I have a chat and mobile text box on my email. where did that come from?

it has a drop down menu with your status and such. where or how do you get that option? do you have to sign up for it?
I have a chat and mobile text box on my email. where did that come from?
Since January 29 Yahoo is slowly introducing IM and SMS to all mail classic users.


http://www.imessengr.com/2009/01/yahoo-c...


http://overview.mail.yahoo.com/classic/c...