There have always been lots of models for how to buy stuff. Buy it outright, lease it to spread the cost and then look after it, or lease it and let the owner keep it maintained. Now software is as important to running our world as buildings and tractors, we are seeing the same sort of options arise. And hence the emergence of SaaS: Software as a Service
So what is it, why is it popular, and what concerns should you address, before taking on a SaaS contract?