Min Ming Lo breaks down all the different share icons in existence today.
Personally? I'm digging his "milkshake" proposition. I even like the unintentional reference to There Will Be Blood (or was it?).
At the end of the day, icons—like English, Chinese or Spanish—are a language. In case of the Share icon, there's different ways of representing it. Some representations are more obscure than than others, but they're dialects and dialects are neither right nor wrong, they just are (well, technically, it's it's called soda, not pop).