I believe part of it is that in Brazil, at least for cell phones, only the caller pays, not the receiver of the call as well (as is the case in the US). It's p

I believe part of it is that in Brazil, at least for cell phones, only the caller pays, not the receiver of the call as well (as is the case in the US). It's pretty common to leave a short message of the form "call me back", or just a missed call - a longer message wastes your minutes.