Mac users are still being treated like red-headed stepchildren when it comes to Yahoo Messenger. No voice chat, no real feature parity compared to the Windows version, and it seems like nothing we say to them can solve the problem. I've contacted Yahoo several times saying that we should have feature parity, but apparently Yahoo has their collective heads up their collective butts and refuses to do anything about it. Every time I've sent a feature parity request to them, I got greeted by the exact same item:

Hello,

Thank you for writing to Yahoo! Messenger.

We understand that you would like to update the Mac version of Yahoo!
Messenger.

For now, we don't have an exact schedule stating when the Mac version
of Yahoo! Messenger will be updated. We appreciate your suggestions a
great deal, as it is through user comments and feedback that we are
able to continue to make improvements. We always have something on the
drawing board, and many of our best new features have been suggested
directly by users like you.

We apologize for the inconvenience this may have caused.

Thank you again for contacting Yahoo! Messenger.

This message essentially says "screw you, we're doing what we want" when what should have been done was something like "OK, we'll forward this request (along with the 10,000 other requests for feature parity) to our development team. Clearly, this is something that needs addressed."

So, the only thing I can truly recommend at this time is to go to Skype if you want cross platform video chat or go to Adium for a regular IM client. Don't even waste your time working with something that Yahoo clearly does not care about.