A heart symbol. Oftentimes used with an object within it, such as <icecream3, meaning that the person loves ice cream. Alternative use: <3 icecream, icecream <3
This has many meanings.
Some common ones are Less than three <3, a sideways heart <3 (normally meaning love), and a face <3.
The < is the eyes/eyebrows, in a.. well, happy position. Kinda. And the mouth, 3, is like an animal mouth. Kinda.
Such as :3, =3, ;3, and so on.
But basically, whether a heart or a happy face, the meaning usually comes out as love or happiness.
Ad more threes and exclamation marks to show that the emotion is more.
I <3 Kitties.
omgz! <333!! Thankyooo!
Less than three <3 and more than one >1