If Windows Phone 8 is going to continue to make a move and compete with iOS and Android, there are many out there who believe that the platform will have to include a voice activated personal assistant like Siri or Google Now; Stefan Weitz, senior director for Bing, apparently feels that a Windows Phone version of the pair will have to have more capabilities than either personal assistant...
Source: http://www.phonearena.com/news/Microsoft-No-personal-assistant-for-Windows-Phone-until-it-is-revolutionary_id45872
Source: http://www.phonearena.com/news/Microsoft-No-personal-assistant-for-Windows-Phone-until-it-is-revolutionary_id45872