Software as a Service (SaaS)

Saas is becoming more prominent. Use Google? You're using SaaS. What does SaaS rely on - Open Source software. Get the lowdown. Software should be treated as service - its not manufactured in the same way as desks for example, and 70/80% of the software life cycle is spent on implementation and maintenance. It would be like spending £10k on your nice BMW, only to find that your need to spend £80k to maintain it - give the BMW away and provide a service (note: this is an analogy).