Works both ways mate, seen many a shorting guru on HC post down ramping comments which are pretty far fetched to place the seed of doubt in your typical mom and dad holders, I imagine you have seen the same. Personally I'm not a big fan of the practice as I go long on the company's I buy and in this climate any shread of bad news and you get pumped you know where by shorters to a certain extent !
End of the day if it makes you money then thats what this games all about, glad naked shorts do no longer a factor in Australia at least.