Know your cloud from your elbow

Cloud computing, grid computing, utility computing, Infrastructure as a Service (IaaS), Platform as a Service (PaaS) and Software as a Service (SaaS), public cloud, hybrid cloud. 

Confused?

I was until I read this excellent post from Kate Craig-Wood who puts it all in context. I thought I understood it all but then I made the mistake of watching this video from explainingcomputers.com - the presenter introduced a new phrase Hardware as a Service (HaaS) - dohhhh!  I think HaaS is what Kate calls utility computing.  

And techies wonder why people get confused by all this stuff.