"Upgradation", simply means learn from your past experiences and make efforts to change your present and future to attain more and more satisfaction. From the era of single job processing to batch processing and then to multiprocessing, we have updated our work process, computing environment, business rules and so on. With the advent of increased awareness of IT in common man, everyone wants to upgrade themselves. IT companies provide software that can install on client machines and produce outputs as per requirements of client. But it will be more advantageous when different kind of software will be made available at one place for usage. This paper aims in providing functionalities of SaaS, types of software as a service, types of SaaS users and certain important software metrics that are required to check the performance of SaaS.