Person 1: "You're never the only one!"
Person 2: "You're never the only one idiot!"
Person 3: "Idiot, you're NEVER the only one"
Person 4: "Yeah, you can never possibly be the only one!"
Person 5: "We are so LOGICAL!"
It is used to whore for attention, because if someone is asking whether or not he or she is the only one, he or she should already know that the answer is "no," yet proceeds to ask anyway. Thus, "am I the only one" disguises a statement of opinion as a question.
It is also used to convince oneself that one's opinion is a unique, nonconformist take on things and everyone else are sheep (or worse yet, sheeple).
Dude: No, idiot. Everyone else who doesn't care about Iron Man 2 doesn't waste their time looking for discussions on Iron Man 2.