Because it looks damn classy.
This is usually placed after a very pathetic subliminal message post- written in the hopes that a certain person will read it... and think more of it.
Because you used TWO semicolons.
And a heart.
"&&i dont know if you love me too;; but forever i will be by your side no matter what happens because you are my angel darling baby boo;;♥"
See also: &&