So you are curious to find out if two people you know on Facebook already; knows each other. And you even want to know, the kind of relationship they have? Are they close friends or only acquaintance.
Off-course there is no 100% solution for this, but there is one simple trick that will give you a lot more information about any two people’s relationship on Facebook.
When you want to find out if two people already know each other or wants to study their relationship, then copy the paste the following URL and replace the  username1 and username2  with the Facebook’s username of those people.
https://www.facebook.com/username1?and=username2
This link will bring you to a page listing their mutual friends, photos, and events that they both have shared together. The good part is, it’s not necessary to have those people in your friend list. You can check the relationship between any two people all you need their username.
If you scroll down, you can see years appearing on the left side of the screen. Clicking on them will give
exact information that is publicly available in that particular year; like wall post, life events, birthday wishes, etc. Therefore using this stats you can guess the kind of relationship they have which would have been difficult otherwise.
