Are you a user of these Apps / social networks and want to find someone in particular, with a username or email? Or, are you one of our readers who has heard plenty in the media about them and wants to know what exactly they are about? Then what you are looking for is a reverse user lookup tool.

We’re going to introduce you to exactly what these Apps are, who tends to use them, and why. We’ll then move on to how on earth you check whether a particular username or email is using them, and how to find their profile.