The emotion engine is the CPU chip in PS2s and the first backwards compatible PS3s. It essentially enables the playing of PS2 games. So, if Sony patent emulation of this emotion engine, it logically leads to speculation that PS2 backwards compatibility is on it's way to a PS3 near you, via firmware updates.

Exciting news, but we don't know for sure if we're going to get any bc-goodness any time soon, if at all. However, feel free to speculate in the comments.