It occurs to me that we are living in a Cambrian period of communications.  Communication itself has a very long history - as long as ours to be sure.  In the beginning, we communicated with sound and gesture.  Then we learned to communicate via symbols in dirt, rock and later clay tablets.  We used fire and smoke as communication tools too.  And then there was paper, which came on the scene and has never left.  We did a lot with paper.  We folded, we rolled, we bound and we pressed. 
Then, not too distantly, we learned a little something about electricity and it wasn't long before we are communicating with it along wires.  Now the forms of communication diversify like nothing we've seen before.  We see the emergence of the telegraph and the telephone.  We start communicating via stored media too.  We write on vinyl and then magnetic tape, then optical media.  We communicate via radio, television and film.  At some point, we throw the transistor into the mix, and like a seed crystal in a super-saturated solution, we precipitate a vast myriad of new forms and devices.  We are communicating now with computers, chat / IM, E-mail, web sites, blogs, video conference, cellular phones, two-way pagers, SMS, picture phones, WiFi, an incredible diversity of technological phyla whose ultimate purpose is simply -- to say hi.