I agree! In the world today I think of it as a courtesy. It could just be a very quick acknowledgement. It's not like people have to pick up the phone and put a lot of time in if they are very busy. Definitely one of my pet peeves
I agree.. I can't stand getting a delivery and read receipt back, but never an actual reply. I give most people the beneft of doubt and give 24 hrs before I send back another email asking WTF, but in nicer terms.
I have been trying to contact a client for 3 days now on an urgent matter, and i know they are in the office. More annoying is the fact they are not replying to voicemails!
I always return an email saying thank you or i will reply when having looked at the correspondence in more detail.