http://www.pcworld.com/article/2100900/bbm-coming-to-windows-phone-nokia-x.html
BlackBerry’s mobile messaging service BBM will be available for Windows Phone and Nokia X users this summer, the company announced Monday during Mobile World Congress in Barcelona.
Nokia X and Windows Phone users will be able to make free voice calls over Wi-Fi or a mobile data connection between BBM contacts on Windows Phone, Nokia X, iPhone, Android and BlackBerry phones, the company said. They will also be able to chat one-on-one or in groups with up to 50 people and can share photos, documents and voice notes, among other things.