Used to show that something (placed to the left of the less-than sign) is less than 3333. Sometimes used by female/homosexual male internetters to mean "Much Love" or "Four-times the love", a play off of the symbol "<3". However, they are incorrect, and merely stating that the person to left left of the less-than sign is less than 3333.
Girl: 3332 <3333
in this case, the number 3332 is less than 3333.
Girl: Andy <3333
In this case, Andy is a person and cannot be less than 3333.