My first experience of AWS was when I was talking to a PHP developer shortly after the first iPhone had been released. He was telling how he had started to store his website images in AWS S3. I was like "wtf is this guy talking about". I went home and googled it.
Here is a great article on AWS S3 btw:
Seeing AWS S3 for the first time reminded me of seeing VMware Workstation (pre ESX) for the first time, I didn't quite know what I was actually looking at, then about 30 mins later when having a cup of tea, the penny dropped.
That was my first intro into real Cloud computing.
What as yours?