There’s been a good deal of fuss recently about the privacy concerns granted to Facebook Messenger when users install and grant access to the app on a mobile device. The concerns in the media go back to December of 2013, but as of April 2014 it’s mandatory to use Facebook Messenger on mobile platforms if you want to send and receive private messages with Facebook. Personally I don’t use Facebook Messenger at all. If I want to send or reply to a Facebook private message, I use the Facebook web interface on my computer. You can decide for yourself what you want to do.
Read this article and decide for yourself how concerned you are about Facebook’s requested permissions when you install Facebook Messenger on a mobile device: http://www.huffingtonpost.com/sam-fiorella/the-insidiousness-of-face_b_4365645.html