Data integration is critical to SaaS
The SaaS model ignores all the issues of reusability and integration with the existing world. It's actually been a boon to our data integration business for companies investing in SaaS to be able to bring back the data into the enterprise, clean it and ensure that it is accurate.
Checkout some of the data integration issues with SaaS at http://blogs.informatica.com/ondemand/
Don Tirsell
Informatica