SaaS Is the King of All
Of all the three models of cloud computing:

• IaaS
• PaaS
• SaaS

SaaS (Software as a Service) is the one that has the most appeal and potential to evoke interest from enterprise CIOs, due to the following reasons:

• This is the most cost-effective way to deploy new business capability
• Lower total cost of ownership (TCO)
• Unmet performance expectations and not meeting the go-to-market pressures with data center-based solutions
• No maintenance, patching, licensing issues enable the business to concentrate on their core strengths
• Wide range of choice and healthy competition already in the market and growing
• Traditional ERP-packaged software is too costly yet not satisfying all the needs of the enterprise

With these in mind, the popularity of SaaS is expected to grow several times in the near future. However, if you are providing a SaaS-based application to your consumer, how best to adapt this is key to winning business. Because no SaaS consumer would like to see that their SaaS solution is not scaling up to changing business needs and they still need to invest in custom in-house solutions.

The following points will help the SaaS application providers make their SaaS application really extensible so that a larger group of consumers can use the same.

1. Provide Ad Hoc and User-Defined Reporting
For a specific set of federal, state-specific compliant reports, no two organizations are going to have the same reporting needs, even if the application's business context (supply chain, purchasing, CRM) are the same. Varied business users, geographic location, organizational score cards and metrics ensure that each organization has its own need for reports.

Developing all the reports needed for every organization using the SaaS application is not feasible. The solution is to provide ad hoc reporting features, so that users can create and define their own reports.

This feature is not new; several of the reporting tools provide user-defined ad hoc reporting as part of their stack.

However, instead of custom developing ‘ad hoc reporting' capabilities within your SaaS application, it is better to link it with another SaaS reporting solution.

For example, if your SaaS application is built on the Microsoft Windows Azure platform, it is easier to offload the ‘ad hoc reporting' to SQL Azure Reporting.

With several features for both ad hoc reporting and custom reporting, SQL Azure Reporting, which will be available shortly, leads the reporting platform on cloud.

2. Enable Business Rules to Make SaaS Flexible Between tenants
A business rule management system (BRMS) enables organizational policies - and the operational decisions associated with those policies, such as claim approvals, cross-sell offer selection, pricing calculations and eligibility determinations - to be defined, deployed, monitored and maintained separately from the application code.

As I explained in a previous article on Private Clouds And Business Rules, Business Rules usage increase the adaptability of the SaaS applications to multiple tenants.

3. Design with Adaptability in Mind
Several major ERP players have designed their software, in a adaptable way, so that the entire way the software runs can be tailored for individual organizations. For example, in Oracle E-Business Suite, flexfields provide an adaptive framework to let any company define the hierarchies specific to them, and yet the overall software works out of a single code base.

A flexfield is made up of sub-fields or segments. A flexfield appears on a ur form as a pop-up window that contains a prompt for each segment. Each segment has a name and a set of valid values.

There are two types of flexfield.

• Key Flexfield: Key flexfield are flexible enough to let any organization use the code scheme they want without programming. Key flexfield can be used to represent code that is made up of meaningful segment to identify GL a/c Part no. and other business entities. Oracle apps store these codes in key flexfields.
• Descriptive Flexfield: They provide customizable expansion space on ur forms. You can use desc flex fields to tract additional information important and unique to ur business that would not otherwise be captured by the form.

4. Link Authentication back to Enterprise Directories
The biggest concern for CIOs for SaaS is security. Every organization has invested a lot in their on-boarding mechanisms and employees have been kept in directories. It would be highly adaptable for SaaS applications to offload the authentication to enterprise directories so that the organizations will be more adaptable to using SaaS applications.

Again this can be done easily if you choose the PaaS platform that is used to build the SaaS application carefully. For example, Windows Azure Appfabric Access Control lets you get authenticated against in-premise directories. The following diagram, courtesy of the vendor, shows the authentication of the SaaS application shifted to several on-premise and external authentication providers.

5. Select an Upgrade Friendly PaaS Platform
The less down time an application has or performance impact due to a guest  operating system, upgrades or patches are the best  for the selection of a SaaS application. For that the PaaS platform on which the SaaS application is built holds the key.

Windows Azure guest OS Auto-upgrade feature to help you keep your service running on the latest operating system available for Windows Azure. The platform automatically upgrades your service to use the latest OS whenever it becomes available without you have to worry about it. This helps you keep your service running on the most secure OS available for Windows Azure with no extra effort.

Summary
Enterprises are looking into SaaS to reduce TCO and be  agile to changing business needs , however, they would not  like to get disruptions or   the SaaS application  not have flexibility between  tenant to tenant, choosing the correct PaaS platform and designing the systems with Adaptability  in mind will improve the marketability of the SaaS application.