The proper use of "Facebook Handle"

The proper use of "Facebook Handle"

Open a subscriber from your email list. e.g. Subscribers > All Subscribers >  zoho@zoho.com
Now head to the "Social Information" of the contact. There you'll have handles for twitter, linkedin and facebook.

This certainly looks to be a very promising feature. But what exactly is the function of this?

Apologies if it's been answered elsewhere, I couldn't find anything related in search.