Theres some surprise news out of Barcelona today: BlackBerry CEO John Chen told CNBC that hed be willing to sell the companys BBM chat service… for the right price. Maybe that isnt much of a surprise after all, considering BlackBerry has a market capitalization of roughly $5.5 billion. Of course, anyone comparing BBM to WhatsApp ought to have their head examined. BlackBerrys messaging client — unlike Facebooks latest acquisition — isnt a growth business, and it has less than 20 percent the active users of WhatsApp.