Nelson Minar's latest blog post has a nice bit about the continuing evolution of heart emoticon (<3) among gamers:
<3 is a little sideways heart, to express love. Usually used ironically in response to a bitchy joke, or in apology for making said bitchy joke. Variants include </3 for a broken heart, <$ to convey a financial motive for love, and <4 as the superlative of <3.
<4 is just brilliant.