Software as a service (SaaS) is one of the quickest growing cloud market. Many companies want to use the ready made software solutions provided by the SaaS providers to store and process their data in the cloud. So, they can access from anywhere, using any device at any time. SaaS Providers also giving 24×7 support to the users, so the companies can focus on their core products instead of managing their Software development life cycle.
Here is an interesting info-graph about the SaaS companies from Founding to IPO (initial public offering) in the year of 2013 and forecasts of 2014.
You can find more details about SaaS providers IPOs in the last 10 years beginning from Salesforce here