Why do we gossip? Gossip is a very human entity that starts from childhood. Just the other day, my 8-year-old cousin and her friend were caught passing notes in class, the content of which was comments about their classmates. Although they weren't being malicious, this shows how human it is to gossip. Humans are thrilled by drama, this is why soap operas are so successful!
As others have stated before, gossiping enables us to socially fit in; we learn what is acceptable behaviour so we do not end up being a topic of gossip. Why do we as humans find it thrilling to "spill the tea?" Learning of another's misfortune gives us a sense of schadenfreude, "at least my life isn't as bad as theirs."
So where do we draw the line between fueling our need for superiority and trampling on another's dignity and right to privacy?
Very interesting discussion you have going here...