So often I think systems developers lose touch with the systems they put out there.
I'll focus this comment on Software as a Service for the moment. SaaS can be delivered as a single or multi tenant offering. The basic difference is that Single tenant is designed for each individual client/company and hosted in such a way that a change to their software will not affect the software of other client/companies hosted on the same servers. Multi tenant is a one software fits all approach and any change will need to be adopted by all clients/companies who subscribe to that software. The multi tenant approach is becoming ever more popular and is starting to fall under the banner of the "Cloud."
Once again I'm going to narrow my focus down to the Multi tenant offering. This model relies on a large client base who subscribe for a low cost ,subscription based pricing model. There may of course be deviations to this basic pricing model and you can read all about the topic in William Blares L.L.C.TECHNOLOGY:SOFTWARE & SERVICES September 26,2007Industry Report.