Hallows Quest

The effect of having made his diary into a Horcrux is noticeable only to Tom Riddle: when he has it with him, people enjoy his presence. When it's back in his dormitory, people avoid him. When a girl by the name of Lovegood starts talking about three Hallows that can make the beholder Master of Death, and a wand more powerful than any other, he's glad he has it with him today.