My theory is that OOO's are (in general) short, and short messages have a tendency to end up in spam folders. The fact that people often don't use the spam butt

My theory is that OOO's are (in general) short, and short messages have a tendency to end up in spam folders. The fact that people often don't use the spam buttom as a delete button probably doesn't help. Also, Gmail is a common source of spam, and they often end up in RBL's.