Well no comet has ever caused any significant doom on this planet while mankind has been around and i don't expect this new comet in 2013 to do anything different!

The only time i might start worrying is if it really is going to pass between Earth and Moon that's a close encounter.

Many people say it will hit the sun and cause Solar doom but that's a crock of shit. It's made of ice it will melt before it even gets close!