The heart shape is symbolic of emotions
including love, affection and
especially romantic love.
The familiar heart shape became popular in
Europe during the 16th century,
and has been popular ever since.
Hearts are even used as the symbols for health
in video games like
The Legend of Zelda and
Super Mario Bros.
In 1977, the heart symbol
started bring used as a verb
when p.r. for the state of NY
introduced the phrase
"I ♥ NY".