Courtesy

Is it me, or do others feel the same ? I am sometimes at a loss to understand why people contact you and when you follow it up, they just spend endless time exchanging pointless messages. Surely if someone has initiated contact and you reply, is it too mcuh to expect some kind of reply, rather than silence. Also is it common on here for people just to ignore any message sent by others. After all, I really did think there may be some genuine people here, or am I just being naieve ? I mean, courtesy costs nothing !!