Sweethearts, conversation hearts.
These candies are definitely desirable. They consume 40% of the Valentine’s Day candy market, still made close to Harvard University in Revere, MA. First appearing in 1847 by Oliver Chase. In the past you would first see these messages on scallop shells with messages inside like a fortune cookie. Later, they were changed into hearts, and stamped with vegetable dye messages. The main market is in the classroom, though the nostalgia has pushed them into the hearts of millions for years after.