Silent Conversations

A young miserable boy Dan forgets his personal diary in a library. He had bought the diary recently during new year. Later when he returns in search of his diary he couldn't find it. He searched in the library but it wasn't there nor the librarian knew anything about it. But 2 days later when he visited the library again he found his diary exactly where he left it. Moreover someone has even written something in it. Intrigued by this incident and out of curiosity he leaves his diary there intentionally and the diary again disappeared but appeared back after a day with a new entry in it by the same unknown person. Who's this unknown person? What did he write in Dan's diary that intrigued Dan? To find out read the story.