Not that it works perfectly, but the default of dumping everything into email is a problem. There are several other, possibly more appropriate methods of communication (phone, in person, waiting until the status meeting, break room chat, lunchtime chat, etc). Email is just the easiest and therefore most likely to be abused.
Personally I prefer email for this reason. Too often I've seen coworkers who become "the guy who helps". The guy doesn't say no, who answers questions that have nothing to do with their job. I like to be helpful but I don't want to be the one who fixes everyone else's problems to the detriment of getting my own work done. It's easier to say "you should ask Joe, he's in charge of that process" in an email, for me anyways.