Facebook has announced that David Marcus, president of PayPal, is headed to Facebook to lead their mobile messaging division. 

Marcus has been at PayPal since 2011, when he joined as the VP of mobile. Since then, PayPal has grown their mobile payments business dramatically. Now, he's headed to Facebook which leaves everyone asking: why? Because Marcus is going to help Facebook monetize Messenger. 

Facebook Messenger is now a standalone app with 200 million users per month, and that's what Marcus will be working on. Facebook gave a very corporate-y explanation of the hire: "We’re excited by the potential to continue developing great new messaging experiences that better serve the Facebook community and reach even more people, and David will be leading these efforts." 

Their press release did note Messenger's large user base — 200,000,000 is a lot of potential spenders. They also have the recently acquired power of WhatsApp behind them, as well. So, my logical conclusion: Marcus is coming to Facebook to help Zuckerberg cash in on users chatting, either by charging for the service in some way, or by going the Gmail route of allowing users to send cash as an attachment.