IaaS : Infrastructure as a ServiceHere is a collection of slideshows about IaaS, Paas and SaaS.
eg: Amazon EC2, Rackspace, Verizon Private Cloud.
PaaS : Platform as a Service
eg: App Engine, Azure.
SaaS : Software as a Service
eg: Google Docs, Acrobat.com.
Application cache (appcache) is a powerful feature in HTML5. However, it does come with baggage. Many (see links below) advocated ferociously against it due to tricky issues it comes with. For someone who is just testing waters, these issues may throw them off grid. Knowing them before hand helps reduce some unpredictable effects.