The rumour that Apple is looking into integrating Siri on his OSX is taking bigger space as recently a new job posting from Apple website under the category ' Siri UX Engineer with experience on Mac OS' appear. In fact the post itself never mentioned the platform on which Siri make 1st appearance IOS instead it went all about integrating Siri to other programs.

It seems that the chances of listening the 'What can i help you with.' on your Mac Pro are getting real.