1. Multi-Tenant, Shared Systems – Using a single instance of an application to serve customers.
2. Trusted Reliability and Performance – Must have 99.9% and sub 300 Milliseconds per transaction. Has to be a transparent service
3. Democratization of Enterprise Applications –needs to serve 1 – 10,000 users all in the same fashion
4. Metadata-Driven Customization – The ability for SaaS users to define and customize the application – Language, business terms etc.
5. Mash-Ups –Leveraging the community and other services seamlessly into the application.
6. Web Services-base Integration – The web service API must be standard based to achieve the snap on functionality and collaboration demanded
7. Development as a Service –Example: Informatica’s PowerCenter Connect a family of data access options that provide broad, metadata-driven, high-performance data interchange for enterprise data integration initiatives. PowerCenter Connect includes options for accessing ERP and CRM systems, message-based real-time/EAI engines, industry standards-based data formats, relational and non-relational databases, and remote cross-enterprise data sources.
8. Application Exchanges - The ability to add and embed applications quickly and easily
9. Multi-Application Delivery – The ability to define access to applications and bundle them together to suite the needs of users on the fly.
10. Multi-Device Delivery – Write the application once and run it everywhere, Blackberry, Palm, etc.
Right now I like what a company called JamCracker http://www.jamcracker.com/ has to offer. Although Rearden and OpSource offer compelling solutions in this intergration space as well.