Good question. I remember Microsoft had an app around 2010, but it just failed to gain critical momentum, maybe because people were already moving en masse to Facebook and WhatsApp itself.

The app was only ok-ish. There were some alternative apps in the AppStore. But people just preferred talking trough WhatsApp and Facebook Messenger (which was already two years old at this point). I guess people gravitated to WhatsApp because it was less cluttered and snappier, and to Facebook because it also had a proper social network in it, but I have no idea. Two years later Microsoft would kill MSN and integrate it with Skype.