More about chat being discontinued;
http://help.yahoo.com/kb/index?page=content&y=PROD_MSNG&locale=en_US&id=SLN8407

The reason they're ending support for Windows Live Messenger is because Microsoft is focusing on Skype. Microsoft plans to discontinue Windows Live Messenger(MSN Messenger) by March 2013. They've been encouraging users to merge Microsoft accounts with Skype.

So there is no misunderstanding Yahoo! will continue to support Yahoo! Messenger the same way Microsoft did when they discontinued chat. Essentially you'll have the pager functions without chat. Voice conferences will still work probably.

It's been speculated for years that Yahoo! would end chat and with today's announcement it has been confirmed.